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Title:
Evaluation of the efficacy of the minimum size rule in the red grouper and red snapper fisheries with respect to J and circle hook mortality, barotrauma and consequences for survival and movement
Physical Description:
Book
Language:
English
Creator:
Burns, Karen Mary
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University of South Florida
Place of Publication:
Tampa, Fla
Publication Date:

Subjects

Subjects / Keywords:
Lutjanus campechanus
Epinephelus morio
Undersized bycatch
Management implications
Ecomorphology
Dissertations, Academic -- Marine Science -- Doctoral -- USF   ( lcsh )
Genre:
non-fiction   ( marcgt )

Notes

Summary:
ABSTRACT: Although closed seasons, bag limits and quotas are used to manage fishes within the Grouper/Snapper Complex off the southeastern United States, size limits are the cornerstone of fisheries management. Because fishers must release all undersized fishes despite fish condition, this regulation has created a mandatory catch and release system. Inherent in this management strategy is the supposition that these undersized fish survive in sufficient numbers so as to justify this regulation. To satisfy this criteria fish mortality must be low and released fish must also experience minimal sub-lethal effects. Determination of sublethal effects and evaluation of their potential impairment and duration of injury are required to develop effective physiology-based criteria to evaluate the efficacy of the minimum size rule. The goal of this research was to evaluate some aspects of the efficacy of the minimum size rule in the red grouper and red snapper fisheries off Florida by collecting traditional fisheries data and analyzing it in light of fish physiology, ecomorphology and behavior.Study objectives included 1) determination of the causes for the differences of hook mortality for red grouper and red snapper in the recreational and recreational-for-hire fisheries by necropsy of acute and latent mortalities, analysis of tag and recapture data for both J and circle hooks, determination of fish dentition and any differences in feeding behavior, 2) examination of the effects of rapid depression from depth on fish survival by inspection and comparison of the red grouper and red snapper swim bladders in both healthy and swim bladder ruptured fish from various water depths, comparison of tag and recapture data, investigation of the effects of fish venting, and laboratory simulations using fish hyperbaric chambers to determine healing and survival from rapid depression trauma, 3) analysis of movement patterns of tagged fish and 4) evaluation of some of the consequences imposed by the minimum size limit based on study results.
Thesis:
Dissertation (Ph.D.)--University of South Florida, 2009.
Bibliography:
Includes bibliographical references.
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Mode of access: World Wide Web.
System Details:
System requirements: World Wide Web browser and PDF reader.
Statement of Responsibility:
by Karen Mary Burns.
General Note:
Title from PDF of title page.
General Note:
Document formatted into pages; contains 184 pages.
General Note:
Includes vita.

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aleph - 002029512
oclc - 436937132
usfldc doi - E14-SFE0002928
usfldc handle - e14.2928
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ABSTRACT: Although closed seasons, bag limits and quotas are used to manage fishes within the Grouper/Snapper Complex off the southeastern United States, size limits are the cornerstone of fisheries management. Because fishers must release all undersized fishes despite fish condition, this regulation has created a mandatory catch and release system. Inherent in this management strategy is the supposition that these undersized fish survive in sufficient numbers so as to justify this regulation. To satisfy this criteria fish mortality must be low and released fish must also experience minimal sub-lethal effects. Determination of sublethal effects and evaluation of their potential impairment and duration of injury are required to develop effective physiology-based criteria to evaluate the efficacy of the minimum size rule. The goal of this research was to evaluate some aspects of the efficacy of the minimum size rule in the red grouper and red snapper fisheries off Florida by collecting traditional fisheries data and analyzing it in light of fish physiology, ecomorphology and behavior.Study objectives included 1) determination of the causes for the differences of hook mortality for red grouper and red snapper in the recreational and recreational-for-hire fisheries by necropsy of acute and latent mortalities, analysis of tag and recapture data for both J and circle hooks, determination of fish dentition and any differences in feeding behavior, 2) examination of the effects of rapid depression from depth on fish survival by inspection and comparison of the red grouper and red snapper swim bladders in both healthy and swim bladder ruptured fish from various water depths, comparison of tag and recapture data, investigation of the effects of fish venting, and laboratory simulations using fish hyperbaric chambers to determine healing and survival from rapid depression trauma, 3) analysis of movement patterns of tagged fish and 4) evaluation of some of the consequences imposed by the minimum size limit based on study results.
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PAGE 1

Evaluation of the Efficacy of the Minimu m Size Rule in the Red Grouper and Red Snapper Fisheries With Respect to J and Ci rcle Hook Mortality and Barotrauma and the Consequences for Survival and Movement by Karen Mary Burns A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy College of Marine Science University of South Florida Major Professor: David A. Mann, Ph.D. Joseph J. Torres, Ph.D. Ernst B. Peebles, Ph.D. Gabriel A. Vargo, Ph.D. Gary R. Fitzhugh, Ph.D. Date of Approval: April 3, 2009 Keywords: Lutjanus campechanu s, Epinephelus morio, undersized bycatch management implications, ecomorphology Copyright 2009, Karen Mary Burns

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Dedication This dissertation is dedicated to my family, especially my parents Helen and John Burns, my aunt Ann Burns, and to my good friends Marvin Tinsky, the Tinsky Family and Dr. Bernie Waxman who made my education pos sible, to Peter Simmons III, Jay Sprinkel and Janet Gannon for their help and encouragem ent and all the staff ,student-interns and volunteers who worked in the Mote Marine Laboratory Fish Biology Program during the years of my tenure and all th e fishers who participated in the research conducted to accomplish this task and to Ja net Giles and Linda Franklin for editing this document.

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1 Acknowledgements Federal funding from NOAA/NMFS MARFIN Awards NA87FF0421, NA97FF0349, NA17FF2010, NOAA/CRP Award NA03NMF4 540417 and Florida Sea Grant Award NA76RG0120 funded this work. I am indebted to my Committee David Mann, Jose Torres, Ernst Peebles and Gabriel Vargo of the University of South Florida School of Marine Science and Gary Fitzhugh of the Na tional Marine Fisheries Service, Panama City Laboratory, for their time and encourag ement, helpful advice, support and whose valuable suggestions greatly improved this manuscript. I thank Kumar Mahadevan, Ph.D., President of Mote Marine Laborator y, for allowing me to use Mote Marine Laboratory facilities for writing part of this document. I w ould also like to thank the staff of Florida Sea Grant and NOAA/ NMFS, all the commercial, recreational, and recreational-for-hire fishers, Fish Biology st udent interns and MML staff in particular, the Fish Biology staff past and present, es pecially, Peter Simmons III, Roger DeBruler, Nick Parnell. Carolyn Weaver and Teresa DeBruler and MML staff Jay Sprinkel, Janet Gannon, Joe Nickelson and James Greene and University of Southern Mississippi researchers Nancy Brown-Pete rson and Robin Overstreet. I also wish to thank Ray Wilson of California State University-Long B each for his advice and use of his fish hyperbaric chambers. Thanks are also extended to all the student interns and Fish Biology volunteers, especially Bernard Waxman, DM V, Daniel Weiner, DMV, John Angelini, Joseph Mazza, and Roy Francis for their help with field collecti ons, fish care and

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2 maintenance and necropsy of specimens. Speci al thanks are extended to all the headboat captains and crew who have allowed staff on their vessels and participated in data collection. Thanks are also extended to B ob Spaeth of Madeira Marine Services for providing red snapper and red grouper fish heads for gape and jaw lever ratio determination and coordinating the offshore l ong-line trips and Linda Martin of the Eagle Claw Company for providing some of the circle hooks used in this research. Thanks are also extended to Terry Oppinger for her swim bladder illustrations and Trisa Winteringham and Linda Franklin for typing this manuscript. I am grateful to all those who have contribute d to this research both in the laboratory and at sea. This study could not have been accomplished without all the MML Fish Biology staff, fishers, laboratory volunteers and student inte rns who spent countless hours measuring, tagging and releasing fish, filli ng out and sending in data forms and tag returns, contacting fishers re turning tags to obtain critic al information, helping with necropsies, photodocumentation, assembly of ta gging packets and spending hours on data entry and QA. Special thanks to all the fi sh sitters who spent many hours on long shifts observing fish behavior and monitoring pressu re gauges on the fish hyperbaric chambers.

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i Table of Contents List of Tables ................................................................................................................ ..... iv List of Figures ............................................................................................................... ..... vi Abstract ...................................................................................................................... ........ xi Chapter One: Evaluation of the Efficacy of the Minimum Size Rule in the Red Grouper and Red Snapper Fisheries W ith Respect to J and Circle Hook Mortality and Barotrauma and the Conse quences for Survival and Movement: An Introduction ..............................................................................................................1 References Cited ......................................................................................................5 Chapter Two: Hook Mortality Differences in Red Grouper ( Epinephelus morio ) and Red Snapper ( Lutjanus campechanus ) ....................................................................9 Abstract ....................................................................................................................9 Introduction ............................................................................................................10 Materials and Methods ...........................................................................................13 Acute Mortality ..........................................................................................13 Latent Mortality Direct Observations ......................................................14 Fish Tagging ..............................................................................................15 Dentition and Jaw Lever Ratios .................................................................19 Feeding Videos ..........................................................................................20 Results ....................................................................................................................23 Acute Mortality ..........................................................................................23 Latent Mortality .........................................................................................25 Tag and Release and Circle versus J Hooks ..............................................26 Dentition and Jaw Lever Ratios .................................................................29 Feeding Videos ..........................................................................................36 Discussion ..............................................................................................................39 Acute Mortality ..........................................................................................39 Circle Hooks ..............................................................................................39 Dentition and Jaw Lever Ratios .................................................................41 Feeding Videos ..........................................................................................44 Fish Ecomorphology and Hooks ................................................................44 References Cited ....................................................................................................47

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ii Chapter Three: Differences between Red Grouper ( Epinephelus morio ) and Red Snapper ( Lutjanus campechanus ) Swim Bladder Morphology and How These Differences Affect Survival during Rapid Depressurization .......................................55 Abstract ..................................................................................................................55 Introduction ............................................................................................................58 Methods..................................................................................................................65 Acute Mortality ..........................................................................................65 Swim Bladder Differences .........................................................................65 Swim Bladder Collec tion and Processing ..................................................65 Laboratory Simulations of Dept h Effects Using Fish Hyperbaric Chambers .............................................................................................66 Live fish collection and fish sanitation protocol ........................................66 Laboratory Pressure Experiments ..............................................................68 Year 1 .............................................................................................68 Year 2 .............................................................................................70 Fish Tag and Release .................................................................................71 Fish Tagging ..................................................................................71 Fish Trap Study ..........................................................................................74 Red Grouper Purchased from Commercial Fish Trappers .........................77 Results ....................................................................................................................78 Swim Bladder Differences .........................................................................78 Gross Anatomy ..............................................................................78 Laboratory Simulations of Dept h Effects Using Fish Hyperbaric Chambers .............................................................................................83 Barotrauma Effects of Rapid Decompression From Simulated Depths .....................................................................83 Esophageal Ring ........................................................................................85 Simulated Depths and Controlled Step-Wise Decompression ..................86 Swim Bladder Healing ...............................................................................87 Stomach Prolapse and Healing ..................................................................89 Fish Tag and Release .................................................................................90 Differences in Survival by Fish Length for Hook-and-Line Caught Fishes ...........................................................................91 Tag and Release of Red Grouper Aboard Commercial Long-Line Vessels .................................................................................................93 Fish Venting ...............................................................................................96 Fish Caught in Commer cial Reef Fish Traps .............................................99 Trap Fish Survival by Ascent Treatments ...............................................100 Red Grouper Purchased from Commercial Fish Trappers .......................102 Discussion ............................................................................................................105 Acute Mortality ........................................................................................105 Swim Bladder Differences .......................................................................105 Laboratory Simulations of Dept h Effects Using Fish Hyperbaric Chambers ...........................................................................................108 Hyperbaric Chambers ..............................................................................111 Swim Bladder Healing .............................................................................114

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iii Stomach Prolapse and Feeding ................................................................116 Fish Tag and Release ...............................................................................117 Differences in Survival by Size ...............................................................119 Recaptures Aboard Commercial Long-line Vessels ................................122 Fish Venting .............................................................................................123 Fish Survival by Treatment ......................................................................124 Fish Trap ..................................................................................................125 Grouper from Commercial Fish Traps .....................................................126 References Cited ..................................................................................................128 Chapter Four: Red Grouper ( Epinephelus morio ) Movement Patterns in the Eastern Gulf of Mexico and South At lantic off the State of Florida .........................132 Abstract ................................................................................................................132 Introduction ..........................................................................................................134 Methods................................................................................................................135 Fish Tag and Release ...............................................................................135 Fish Tagging ................................................................................135 Publicity Campaign and Tag Lottery ...........................................137 Data Analyses ..............................................................................138 Red Grouper Movement Model ...................................................139 Red Grouper Movement in Relation to Depth .............................140 Red Grouper “Cohort Movement” ...............................................140 Results ..................................................................................................................140 Red Grouper .............................................................................................140 Red Grouper Movement Model ...................................................142 Red Grouper Movement in Relation to Depth .............................144 Red Grouper “Cohort Movement” ...............................................149 Discussion ............................................................................................................162 Distance from Shore and Size Distribution .............................................162 Movement ................................................................................................163 Red Grouper “Cohort Movement” ...............................................164 Hurricanes ....................................................................................166 References Cited ..................................................................................................169 Chapter Five: Evaluation of the Efficacy of the Minimum Size Rule in the Red Grouper and Red Snapper Fisheries W ith Respect to J and Circle Hook Mortality and Barotrauma and the Conse quences for Survival and Movement: Concluding Remarks ..................................................................................................175 References Cited ..................................................................................................183 About the Author ................................................................................................... End Page

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iv List of Tables Table 2-1. Number of red grouper and red snapper tagged and recaptured by hook type. ......................................................................................................27 Table 2-2. Red snapper recaptu res by hook type and depth. ..........................................29 Table 2-3. Red grouper specimen lengths gape size and upper and lower jaw tooth counts ...................................................................................................30 Table 2-4. Red snapper specimen lengths gape size and upper and lower jaw tooth counts. ..................................................................................................30 Table 3-1. Red snapper and red grouper mortalities during h yperbaric chamber tests. Data include number of mo rtalities for each depth, % of all fish tested by species, % of all fi sh tested at depth by species, and % of all mortalities by depth. ............................................................................83 Table 3-2. Acute and delayed mortalitie s of red snapper and red grouper from hyperbaric chamber tests. ..............................................................................84 Table 3-3. Results of incremental step -wise decompression experiments in fish hyperbaric chambers to determine th e number of pressure increments (number of stops) needed for re d grouper and red snapper to acclimate to surface pressure (1 atm) after acclimation to a simulated depth of 42.7 m (4.3 atm)..............................................................................86 Table 3-4. Results of G tests comparing su rvival by fish length of small to large red grouper and red snapper using all recreational recaptures regardless of depth. .......................................................................................92 Table 3-5. Red grouper and red snapper recaptures by fish length and fishing sector for fishes tagged and recaptured at 21.3 m. Depth was chosen because chamber studies showed 100% survival for both species at this depth. Fish le ngth was chosen because it was the legal size limit for Gulf of Mexico red snapper and for red grouper it provided both consistency and a la rger sample size for analyses .................93

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v Table 3-6. Immediate release fate of red grouper caught, vented, tagged, and released off long-line vessels on obs erver trips by species, tag depth (m), and season. ............................................................................................95 Table 3-7. Red Grouper and red snapper tagged and released in the shallow water control group (fish caught at 21 m) where barotrauma was not an issue that were vented or not vented before release. ................................96 Table 3-8. Red grouper tagged and released by treatment (vented or not vented) by depth. ........................................................................................................97 Table 3-9. Red snapper tagged and releas ed by treatment (vented or not vented) by depth. ........................................................................................................97 Table 3-10. Number of fish caught a nd percent survival rate by depth in commercial fish traps. ...................................................................................98 Table 3-11. Ascent rate of fish retrieved by hand and winch. ........................................101 Table 4-1 Number of single and multiple red grouper recaptures from October 1, 1990-July 31, 2007..................................................................................141 Table 4-2. Summary of variables and re sults of logistic regression movement model. Significant variables (p< 0.05) were Length at recapture (TL cm) and Days at Large. ...............................................................................143 Table 4-3. Results of linear regression on regression using all fish to test the relationship between fish lengt h and distance from shore for significance for red grouper caugh t and measured in the South Atlantic off the Florida east coast. ..............................................................146 Table 4-4. Summary statistics for fish m ovement in relation to changes in depth during movement. Fish were classifi ed into two groups: 1) (labeled as change) those whose movements resulted in a change in depth of 5 m, 10 m, and 20 m and 2) (labeled as no change) those that either did not move or whose movement di d not result in a change of the specified magnitude. The fish that did not change depth were tagged at the same time and place as the fi sh that did not change depths. .............148 Table 4-5. Groups of red grouper that a ppeared to move together. Fish were tagged on the same date at the same location and were recaptured on a different data at a different locat ion. In some cases, groups moved similarly but at different dates; s ee notes. Depth is expressed as elevation so depth readings are expressed negative. ...................................150

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vi List of Figures Figure 2-1. Tag and rele ase sites for red grouper (Epinephalus morio) and red snapper (Lutjanus campechanus). ................................................................. 16 Figure 2-2. Tagging an undersized red grouper prior to release. .....................................16 Figure 2-3. Venting a red grouper. ..................................................................................17 Figure 2-4. Red snapper killed by J hook trauma. ...........................................................24 Figure 2-5. Red snapper killed by J hook macerating the liver. ......................................24 Figure 2-6. Number of red grouper and re d snapper acute shipboard mortalities partitioned by cause of death (depth-related, hooking, other). .....................24 Figure 2-7. Pooled blood in a red snapper that died as a result of latent hook mortality. .......................................................................................................25 Figure 2-8. Percent return of red gro uper and red snapper recaptured by hook type. ...............................................................................................................28 Figure 2-9. Multiple rows of small backward pointing teeth in red grouper top pre-maxilla. ...................................................................................................31 Figure 2-10. Lower jaw dentition of red grouper showing inward pointing teeth. ...........31 Figure 2-11. Red grouper front upper dentition featuring canines. Size reference: each square = 5 mm x 5 mm. ........................................................................32 Figure 2-12. Red grouper front lowe r dentition featuring canines. ...................................32 Figure 2-13. Red grouper upper canines and large gape. ..................................................33 Figure 2-14. Rows of sharp conical teeth in both the red snapper upper and lower jaws. ..............................................................................................................33 Figure 2-15. Red snappe r upper canine teeth. ...................................................................33

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vii Figure 2-16. Lateral view of red snappe r upper jaw showing canines and conical teeth. ..............................................................................................................33 Figure 2-17. Red snapper lower jaw frontal view showing the reduced number of conical shaped teeth in the lower mandible. .................................................34 Figure 2-18. Lateral view of red groupe r upper jaw showing canines and conical teeth. ..............................................................................................................34 Figure 2-19. Lateral view of red snappe r lower jaw. Yellow arrow shows location of ascending process. ....................................................................................35 Figure 2-20. Lateral view of red grouper lower jaw. Yellow arrow shows location of ascending process. ....................................................................................35 Figure 2-21. Red grouper exhibiting ram suction feeding. Note full buccal extension as the entire shrimp is drawn into the fish’s mouth. .....................37 Figure 2-22. Red snapper exhibiting biting feeding behavior caught in the process of biting a shrimp in half before swallowing it. ............................................37 Figure 2-23. Difference in prey residen ce time in the fish’s mouth before swallowing between red sn apper and red grouper. .......................................38 Figure 3-1. Illustration of the close asso ciation of the gas gl ands (gg) and the rete mirable (rm) in the red grouper swim bladder ventral wall. ..................62 Figure 3-2. Series of fish hyperbaric pressure chambers situated over a 1,000liter tank, used in the pressu re simulation experiments. ...............................68 Figure 3-3. Red grouper in one of the fish hyperbaric chambers as observed through the acrylic view plate. Ta gs with unique numbers identified each experimental fish. .................................................................................69 Figure 3-4. Study area where red groupe r and red snapper were tagged. .......................72 Figure 3-5. Fish trap study sites. Water de pths are in meters. Distance is in km ..........76 Figure 3-6. Acute shipboard mortality partitioned by cause of death (depthrelated, hooking, other) .................................................................................79 Figure 3-7. Inflated red grouper swim bladder showing swim bladder size in proportion to total body size. ........................................................................79 Figure 3-8. Inflated red snapper swim bl adder showing swim bladder size in proportion to total body size. ........................................................................80

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viii Figure 3-9. Initial rupture in a red grouper swim bladder. ..............................................80 Figure 3-10. Initial rupture in a red snapper swim bladder. ..............................................81 Figure 3-11. Bilateral post-cranial hemorrhages in red grouper rapidly decompressed from 21.3 m. ..........................................................................81 Figure 3-12. Inner view of the ventral wall of a red snapper and red grouper swim bladder showing the differences in areas of gas absorption and resorption and the secondary struct ure in the red grouper posterior portion of the swim bladder. .........................................................................82 Figure 3-13. Red snapper exhibiting stom ach prolapse caused by swim bladder gas expansion following swim bladder rupture. ...........................................84 Figure 3-14. Pressure induced e xopthalmia in a red grouper. ...........................................85 Figure 3-15. Esophageal ring bruise caused by stomach prolapse in red snapper decompressed from 61 m ..............................................................................86 Figure 3-16. Red snapper swim bladder r upture site showing healing in a fish sacrificed 2 days afte r rapid decompression from the simulated depth of 62 m in hyperbaric chambers....................................................................88 Figure 3-17. Red snapper swim bladder rupt ure scar 3 days after rupture in 62 m hyperbaric chamber rapid decompression experiment. Rupture is healed sufficiently to be functional. ..............................................................88 Figure 3-18. New swim bla dder rupture from depth si mulation of 21.3 m (tip of forceps) and healed scar (tip of scissors) from rupture at 21.3 m during capture one month previously. ..........................................................89 Figure 3-19. Red snapper stomach one hour after stomach prolapse. Stomach is back in place and fish can feed normally. .....................................................90 Figure 3-20. Overall view of red sna pper 7 days after rapid decompression experiment in hyperbaric chamber 42 m depth simulation. Note good condition of tissues and organs and evidence (shrimp) of normal feeding. .............................................................................................90 Figure 3-21. Red grouper immediately following hook extraction after being brought up during a long-line set. Note lack of ex ternal signs of rapid decompression...............................................................................................94

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ix Figure 3-22. Red grouper caught on the sa me long-line set exhibiting various degrees of exophthalmia. ..............................................................................94 Figure 3-23. Commercial trap captur ed red groupers caught at 55-61 m not exhibiting the common external signs of barotrauma .................................102 Figure 3-24. Intact inflated swim bl adder excised from a 70.0 cm red grouper caught by commercial fish trap (55m). .......................................................102 Figure 3-25 Intact normally positioned stomach from a 58.0 cm red grouper caught in a commercial fish trap (55-61m). ................................................103 Figure 3-26. Swim bladder of a 70.0 cm red grouper caught in a commercial fish trap. Note pre-pinhole formati on and semi-transparent stretched tissue of posterior portion of the swim bladder. .........................................103 Figure 3-27. Swim bladder from a 67.5 cm commercial trap caught red grouper exhibiting pinhole trauma (55-61 m). .........................................................104 Figure 3-28. Swim bladder tear in a 5 7.7 cm commercial trap caught red grouper (55-61 m). ...................................................................................................104 Figure 3-29. Bottlenosed dolphin about to feed on an undersized red snapper just discarded from a headboat fishing off Panama City, Florida. ....................121 Figure 4-1. Study area including long distance movements of tagged and recaptured red grouper. ...............................................................................136 Figure 4-2. Graph of a first order linear regression (red line) through the means (red circles) of red grouper lengths (cm) 10 per size class and a first order regression through all fi sh lengths (cyan dotted line) of fish size by distance from shore superimposed over a length/frequency graph of red groupe r captured in the South Atlantic off the Florida east coast and eastern Gulf of Mexico. ...............................145 Figure 4-3. Red grouper movements plotted from recaptures. Because latitude and longitude were recorded to th e nearest minute, not second, to protect exact fishing spots, red gr ouper tagged and released just offshore, appear as if on land. Most recaptures show ontogenic movement offshore. ....................................................................................147 Figure 4-4. Group movement by red grouper near the panhandle of Florida. Grey squares represent locations we re fish were tagged, white circles represent locations were fish were recaptured. ...........................................161

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x Figure 4-5. Group movement by red grouper in the far eastern Gulf of Mexico. Grey squares represent locations we re fish were tagged, white circles represent locations were fish were recaptured. ...........................................162

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xi Evaluation of the Efficacy of the Minimu m Size Rule in the Red Grouper and Red Snapper Fisheries With Respect to J and Circle Hook Mortality and Barotrauma and the Consequences for Survival and Movement Karen Mary Burns ABSTRACT Although closed seasons, bag limits and quotas are used to manage fishes within the Grouper/Snapper Complex off the southeastern United States, size limits are the cornerstone of fisheries management. Because fishers must release all undersized fishes despite fish condition, this regu lation has created a mandatory catch and release system. Inherent in this management strategy is th e supposition that these undersized fish survive in sufficient numbers so as to justify this regul ation. To satisfy this criteria fish mortality must be low and released fish must also experience minimal sub-lethal effects. Determination of sublethal effects and eval uation of their potent ial impairment and duration of injury are required to develop e ffective physiology-based criteria to evaluate the efficacy of the minimum size rule. The goal of this research was to evaluate some aspects of the efficacy of the minimum size rule in the red grouper and red snapper fisheries off Florida by collecting traditional fisheries data and analyzing it in light of fish physiology, ecomorphology and behavior. Study objectives included 1) determination of the causes for the differences of hook mortality for red grouper and red snapper in the recreational and r ecreational-for-hire

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xii fisheries by necropsy of acute and latent mortali ties, analysis of tag and recapture data for both J and circle hooks, determination of fish dentition and any differences in feeding behavior, 2) examination of the effects of ra pid depression from dept h on fish survival by inspection and comparison of the red grouper and red snapper swim bladders in both healthy and swim bladder ruptured fish from various water depths, comparison of tag and recapture data, investigation of the effects of fish ven ting, and laboratory simulations using fish hyperbaric chambers to determin e healing and survival from rapid depression trauma, 3) analysis of movement patterns of ta gged fish and 4) evaluation of some of the consequences imposed by the minimum size limit based on study results.

PAGE 17

1 Chapter One: Evaluation of the Efficacy of the Minimum Size Rule in the Red Grouper and Red Snapper Fisheries With Respect to J and Circle Hook Mortality and Barotrauma and the Consequences for Survival and Movement: An Introduction Red grouper, Epinephelus morio and red snapper, Lutjanus campechanus support important recreational, recreational-for-hire, and commercial fisheries comprising significant portions of the reef fish catch in the Gulf of Mexico and South Atlantic. According to Coleman et al. (2004), “Marine recreational fishing e ffort has increased by over 20% in the past 20 years, rivaling co mmercial fisheries for many fish stocks, including …red snapper.” In 2004, a to tal of 2,041,530 lbs of red snapper and 3,190,281 lbs of red grouper were landed in Florida by these fisheries (NOAA Fisheries MRFSS, Richard Cody, Florida Fish and Wildlife Conservation Commission, personal communication). Shallow water grouper landings, averaging 10.6 million pounds annually (1985-2001), were responsible for appr oximately one half of the aggregate reef fish landings in the Gulf of Mexico and of the six grouper species which account for 95%-98% of total Gulf of Mexico grouper la ndings, red grouper dominated the landings with anywhere from less than five milli on pounds (1992 and 1998) to almost nine million pounds (1989) (Richard Cody, Florida Fish and Wildlif e Conservation Commission, personal communication). With landings averaging 8.3 million pounds annually (19852001), snappers represented 38% of the total reef fish catch and of these; red snapper is the most abundant snapper sp ecies landed in the Gulf.

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2 Because of their importance, both red groupe r and red snapper are highly regulated in both the Gulf of Mexico and South Atlantic Although there are re creational bag limits for both species in the Gulf and South Atlantic and closed seasons for both species in the Gulf of Mexico, these species, like most reef fish fisheries are primarily regulated by minimum size limits in both state and federal waters throughout the southeastern United States. Size limits have long been the cornerst one of fisheries management in the United States. Minimum size limits are intended to prevent growth and r ecruitment overfishing by allowing some portion of fish in a cohort to grow and reproduce at least once before dying of natural or fishing related causes. All fishers must abide by the minimum size regulation and release unders ized bycatch rega rdless of location, water depth, fish condition or predators present. The minimu m size regulation is enforced by prohibiting the landing of fish below the legal size. Enforcement of the minimum size limit rule has created a mandatory catch and release progr am for undersized bycatch. Determining the survival of released undersized bycatch in these fisheries, is critical as undersized bycatch comprise a significant percentage of the to tal catch in the reef fish recreational, recreational-for-hire and commercial fisheries. Un dersized releases in the Gulf of Mexico red snapper recreational fish ery are estimated to be 4050% of the catch (Goodyear 1995). Survival of these discards is essentia l for effective management of these species and critical in determining the e fficacy of the minimum size rule Currently there are insufficient data on the fate of released fishes and survival rates after capture and release. The fate of undersized, released fish depends on a suite of factors contributing to mortality including hook trauma, depth induced mortality, physiological

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3 stress from warm water temperatures, hand ling and increased play ing times (Wood et al. 1983, Tomasso et al. 1996, Gitschlag and Renaud 1994, Bruesetwitz et al. 1996, Chopin et al. 1996, Wilson and Burns 1996, Porch 1998, Collins et al. 199, Cooke and Suski 2004, Bartholomew and Bohnsack 2005). Amo ng these, the causes and effects of hook damage and depth of capture on the mortalit y of undersized red grouper and red snapper in the private recreational and recreationalfor-hire fisheries off Florida are of great interest to those responsible for stock assessm ents and management of these species (Red Snapper SEDAR 2004, Red Grouper SEDAR 2006). In addition to traditional fishery management practices, the creation of marine reserves has been embraced as an important tool in fisheries management leading to a change from single species management to ecosystem management. Both the President’s U.S. Commission on Ocean Policy final repor t (2004) “A Blueprint for the 21st Century” and the PEW Oceans Commission final report (2003 ) “America’s Living Oceans: Charting a Course for Sea Change” stress the need for ecosystem management to reduce bycatch and protect habitat. One of the strategies to accomplish this goal is th e creation of marine reserves to protect marine biodiversity a nd promote sustainable fisheries (Bohnsack and Ault 1996, Meester et al. 2004). To implement this strategy a suite of scientific disciplines (Bohnsack and Ault 1996) and an understanding of the life history, movements, habitat requirements and spatialtemporal dynamics of the living resources, and spatial arrangement and use of these ha bitats by living organisms (Meester et al. 2001, Sobel and Dahlegren 2004) are required. In addition to marine reserves, the Pew Oceans Commission (2003) calls for a decrease in bycatch by determining and enforcing

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4 bycatch mortality limits for fisheries and ri gorous enforcement of regulations of fishing gear that results in high levels of bycatch. Several avenues of research were pursued dur ing the course of this dissertation toward addressing some of the data needs related to the fishery management issues previously discussed. Chapter Two deals with a discussi on of the differences in hook mortality rates for red grouper and red snapper as determined by necropsy of acute and latent mortalities from fish caught during headboat fishing trips. Circle hooks have been touted as the solution for significantly reduc ing hook mortality. A fi sh tagging study incorporating fishers from the private recr eational and recreational-for-hir e reef fish fisheries was conducted to test for differential effects of J versus circle hooks on red grouper and red snapper survival. In additi on, differences in dentition, jaw lever ratios and feeding behavior were examined to determine if and how these factors contribute to observed differences in hook mortality between the two species. Chapter Three addresses depth induced morta lity differences between the two species. Topics include differences in swim bladde r morphology, the effects of rapid changes in pressure on the swim bladder, the effects of swim bladder rupture on survival of each species, swim bladder healing, and the effects of fish venting on fish survival for red grouper and red snapper caught at various depths. Estimates of survivorship to document swim bladder healing and determination of the interval between swim bladder rupture and healing are important because only then is the fish completely capable of returning to its normal lifestyle. Laboratory studies em ploying fish hyperbaric chambers to simulate

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5 the effects of rapid decompression were us ed to study the process under controlled conditions. Since fish were held for at least a month before the rapid decompression experiments began, any detrimental effect s of hooking during initial capture were eliminated from test results. To verify labor atory results, data were gathered during field studies using a tag/recapture study to determin e survival rates of released tagged fish subjected to rapid changes in depth during fishing and the effects of fish venting. In the next chapter (Chapter Four) moveme nt patterns of red grouper are discussed. Movement data were obtained from tag recapture information collected during the field hook mortality and rapid depre ssurization studies. Red grouper movements related to size, movements related to ontogeny and the in fluence of hurricanes were only examined based on data limitations. The final chapter (Chapter Five) is a brief summary of each of the proceeding chapters and a short discussion of the implications study results provide for management of red grouper and red snapper. Central to this disc ussion is an evaluation of the consequences imposed by the minimum size limit regulation on undersized red grouper and red snapper based on study results and the importan ce of including ecomorphology, fish physiology and predation as part of fisheries mana gement for these two species. References Cited Ault, J.S., S.G. Smith, J.A. Bohnsack, J. Luo, D.E. Harper and D.B. McClellan. 2006. Building sustainable fisheries in Florida's coral reef ecosystem: positive signs in the Dry Tortugas. Bulletin of Marine Science 78(3):633-654.

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6 Ault, J.S., J.A. Bohnsack, S.G. Smith and J. Luo. 2005. Towards sustainable multispecies fisheries in the Florida USA coral reef ecosystem. Bulletin of Marine Science 76(2):595-622. Ault, J.S., J.A. Bohnsack and G.A. Mees ter. 1997. A retr ospective (1979-1996) multispecies assessment of coral reef fish stocks in the Florida Keys. Fishery Bulletin 96(3):395-414. Bartholomew, A. and J.A. Bohnsack. 2005. A review of catchand-release angling mortality with implications for no-take reserves. Reviews in Fish Biology and Fisheries 15:129-154. Bohnsack, J.A. and J.S. Ault. 1996. Manage ment strategies to conserve marine biodiversity. Oceanography 9(1):73-82. Bruesewitz, S., D. Fletcher and M. Divens 1996. Hooking mortality of walleye caught from deep water. Washington Department of Fish and Wildlife Research Report No. IF96-07, 7 p. Chopin, F. S., T. Arimoto and Y. Inoue. 1996. A comparison of the stress response and mortality of sea bream Pagrus major captured by hook and line and trammel net. Fisheries Research 28:277-289. Cooke S. J. and C.D. Suski. 2004. Are circle hooks an effective tool for conserving marine and freshwater recreational catch-and-release fisheries? Aquatic Conservation: Marine and Freshwater Ecosystems 14:1-28. Coleman, F.C., W.F. Figueira, J. S. Uela nd and L.B. Crowder. 2004. The impact of United States recreational fisher ies on marine fish populations. Science 305(5692):1958-1959. Collins, M.R. J.C. McGovern, G.R. Sedberry, H.S. Meister and R. Pardieck. 1999. Swim bladder deflation in black sea bass and ve rmilion snapper: potential for increased post-release survival. North American Journal of Fisheries Management. 19:828-832. Davis, M.W. and B.L. Olla. 2001. Stress and de layed mortality induced in Pacific halibut by exposure to hooking, net towing, elevated seawater temperature and air: implications for management of bycatch. North American Journal of Fisheries Management 21:725-732. Gitschlag, G.R. and M.L. Renaud. 1994. Field experiments on survival rates of caged and released red snapper. North American Journal of Fisheries Management 14:131-136. Goodyear, C.P. 1995. Red snapper in U.S. waters of the Gulf of Mexico. NMFS/SEFSC Contributi on MIA-95/96-05. 171 p.

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7 Gulf of Mexico Fishery Management Council Reef Fish Stock Assessment Panel. 2002. September, 2002 Report of the Reef Fish St ock Assessment Panel. A report of the September 17-19, 2002 meeting. Available from the Gulf of Mexico Fishery Management Council, 301 North, Suite 1000, Tampa, Florida 33619. Meester, G.A., A. Mehrotra, J.S. Ault and E.K. Baker. 2004. Designing marine reserves for fishery management. Management Science 50(8):1031-1043. Meester, G.A., J.S. Ault, S.G. Smith and A. Mehrotra. 2001. An integrated simulation modeling and operations research approach to spatial management decision making. Sarsia 86(6):543-558. National Marine Fisherie s Service. 2002. Status of red grouper in United States waters of the Gulf of Mexico during 1986-2001. Sust ainable Fisheries Division Contribution SFD-01/02-175, Southeast Fisheries Center, National Marine Fisheries Service, 75 Virginia Beach Drive, Miami, Florida 33149. Pew Oceans Commission. 2003. America’s livi ng oceans – charting a course for sea change. Available at http://www.pewtrusts.org/pdf/env_pew_oceans_final_report.pdf Porch, C.E. 1998. Estimating Atlantic bluefin tuna mortality from the release and recapture dates of recovered tags. Intern ational Commission for the Conservation of Atlantic Tunas, Collected Volume of Sc ientific Papers, SCRS/98/65, Miami, FL. SEDAR 7. 2004. Red snapper data workshop report. SEDAR. New Orleans, LA. 88 p. SEDAR 12. 2006. Stock assessment report of Gulf of Mexico red grouper. Stock Assessment Report 1 SEDAR. St. Petersburg, FL. 64 p. Sobel, J. and C. Dahlgren. 2004. Marine Reserves A Guide to Science, Design, and Use. Island Press. 1718 Connecticut Ave. Suite 300, NW, Washington, DC. 383 p. Tomasso, A.O., J.J. Isely and J.R. Toma sso. 1996. Physiological responses and mortality of striped bass angled in freshwater. Transactions of the American Fisheries Society 125:321-325. U.S. Commission on Ocean Policy. (2004). An Ocean Blueprint for the 21st Century. Final Report. U.S. Commission on Ocean Policy, Washington, DC. 676 p. Available at http://www.oceancommission.gov/documents/full_color_rpt/welcome.html Wilson, R.R. and K.M. Burns. 1996. Potential survival of released groupers caught deeper than 40 m based on shipboard and in-s itu observations, and tag-recapture data. Bulletin of Marine Science 58:234-247.

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8 Wood, C.M., D.T. Turner and M.S. Graham 198 3. Why do fish die afte r severe exercise? Journal of Fishery Biology 22:189-201.

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9 Chapter Two: Hook Mortalit y Differences in Red Grouper ( Epinephelus morio ) and Red Snapper ( Lutjanus campechanus ) Abstract To evaluate the efficacy of the minimum size rule for red grouper and red snapper a variety of approaches were undertaken to determine the role h ook mortality plays in species survival. The first hypothesis tested was that there was no difference in hook release mortality between red snapper and re d grouper. Necropsy results from headboat client caught fish showed red snapper suffe red the greatest acute hook trauma (49.1%), almost equaling all other sources (50.9 %) of red snapper mortality combined. Only 20% of red grouper acute mortalities were attribut ed to hook injuries. Red snapper latent hook mortality (29%) was also much higher relative to red grouper (7%). Tag recaptures were used to test two null hypotheses; first, that there would be no difference in red grouper recapture rates for fish caught on circle and J hooks and second, there would be no difference in recapture rates of red snapper caught on circle versus J hooks. Both null hypotheses were rejected. Circ le hooks reduced red groupe r but not red snapper hook mortality. Red grouper recaptures were 14.0% (circle) and 7.3% (J) by hook type. Red snapper originally caught on J hooks (12.5%) had a higher re capture rate that those initially caught on circle hooks (8.1%). The next hypot hesis tested was that hook mortality differences resulted from dispar ity in ecomorphology and feeding behavior. Dentition, jaw lever ratios, and feeding type and feedi ng behavior, including prey residence time in the mouth before swallowi ng differed between the two species. Red

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10 grouper dentition included rows of small teet h that occurred on the top and bottom of the pre-maxilla, canine teeth on both the upper a nd lower mandible, and relatively high jaw lever ratios (.17 closing/.24 ope ning) consistent with jaws re quired for suction feeding. Red snapper dentition consisted of rows of larger teeth in both the upper and lower jaws with a reduced number of teeth in the bottom jaw and a set of large canine teeth present in the upper mandible but absent in the lower jaw. Red snapper top canine, top fused and depressible as well as bottom jaw tooth length was longer than those of red grouper. Red snapper dentition was indicative of a predator feeding on soft bodied elusive prey. Jaw lever ratios were high (. 32 closing/.22 opening) signi fying strong jaws. The null hypothesis that there was no difference in pr ey residence time in the mouth (x = red grouper: 6.62 seconds; red snapper: 3.74 s econds and SE = red grouper: 0.419; red snapper: 0.289) before swallowing betw een the two species was rejected as t test mean values were significant ( p =< 0.001). Red grouper and red snapper demonstrate ecomorphological propensities in feeding morpho logy that translate in to specific feeding behaviors that help clarify differences in J and circle hook mortality between the two species and may prove useful in designing pred ictive models for determining J and circle hook mortalities for other species. Introduction Grouper landings, averaging 10.6 million pound s annually (1985-2001), were responsible for approximately one half of the aggregate re ef fish landings. Of the six grouper species which account for 95% to more than 98% of total Gulf of Mexico grouper landings, red grouper ( Epinephalus morio) dominated the landings with anywhere from less than five

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11 million pounds (1992 and 1998) to almost nine million pounds (1989). In 2004, a total of 2,041,530 lbs of red snapper and 3,190,281 lbs of red grouper were landed in Florida by these fisheries (NOAA Fisheries MRFSS, Ri chard Cody, Florida Fish and Wildlife Conservation Commission, personal communication). Red snapper ( Lutjanus campechanus) is the most abundant snapper specie s landed in the Gulf (NOAA Fisheries MRFSS, Richard Cody, Florida Fish and W ildlife Conservation Commission, personal communication). The minimum size rule has created a national catch and release program for recreational and commercial undersized fishes (Cooke and Cowx 2004, Bartholomew and Bohnsack 2005). Coleman et al. (2004) found recreati onal fishing significantly contributed to mortality in a number of marine fisheries in cluding red snapper. Numerous factors can independently or synergistically affect release mortality (Git schlag and Renaud 1994, Murphy et al. 1995, Chopin et al. 1996, Lee and Bergersen 1996, Nelson 1998, Wilde et al. 2000, Davis and Olla 2001, Neal and L opez-Clayton 2001, Burns et al. 2002, Lucy and Arendt 2002, Miljard et al. 2003, Burns et al. 2004); however, trauma caused by hooks is the primary determinant of releas e mortality (Dextrase and Ball 1991, Bendock and Alexandersdottir 1993, Dubois et al 1994, Render and Wilson 1994, Diggles and Ernst 1997, Malchoff and Heins 1997, Albin and Karpov 1998, Bettoli and Osborne 1998, Bettoli et al. 2000, Julliard et al. 2001, A yvazian et al. 2002, Lukacovic and Uphoff 2002, Doi et al. 2004, Lindsay et al. 2004, Bartholomew and Bohnsack 2005). To evaluate the efficacy the minimum size rule for red grouper and red snapper a variety of approaches to determine the effects of hook mo rtality were undertaken. The first was to

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12 test the hypothesis that there was no differe nce in hook release mortality between red snapper and red grouper in the recreational and recr eational-for-hire fisheries. To test this hypothesis hook mortality of red grouper and red snapper captured from headboats was assessed by three methods. Acute mortality was determined by necropsy. Direct observation of latent mortality in fishes held and monitored in 3,406 liter laboratory experimental tanks were monito red. Finally, survivorship of shipboard released fishes was evaluated. In the tag/release portion, hook mortality between species was also assessed by hook type (J versus circle) using tag recaptures as a measure of survival. Circle hooks have been promoted by many within the fishing media a nd some fishery scientists as the most effective means of reducing hooking mortality. Due to the perception that circle hooks are beneficial for all fish species, they ha ve become very popular in recreational and recreational-for-hire fisheries; however, fish survival va ries among species (Cooke and Suski 2004). Results from publishe d hook-type comparisons reve al differential efficacy of circle hooks with dramatically reduced mo rtality for some species (Prince et al. 2002, Skomal et al. 2002, Trumble et al. 2002, Fa lterman and Graves 2002), minimal or no benefit for other species (Malchoff et al. 2002, Zimmerman and Bochenek 2002, Cooke et al. 2003a, Cooke et al. 2003b) and severe injury to others (Cooke et al. 2003c). Recapture results were used to test two nu ll hypotheses; first, that there would be no difference in recapture rates for red grouper caught on circle and J hooks and second, that there would be no difference in recapture rate s of red snapper caught on circle versus J hooks.

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13 Another part of the approach included exam ining fish dentition and mandibles of each species, determining jaw lever ratios and docum enting differences in feeding behavior to assess whether differences in hook mortality we re due to differences in mandible size, shape and dentition resulting in dissimilar f eeding behaviors. The relationship of fish dentition and jaw morphology to fish feedi ng behavior (Motta 1984, Wainwright et al. 2001, Porter and Motta 2004) a nd its relationship to diet (Wainwright 1991, Mullaney, and Gale 1966, Hernandez and Motta 1997, Ward-Campbell and Beamish 2005) have been well established. Thus, the study appro ach was to film red grouper and red snapper in the laboratory to reveal and document feedi ng type and relate feed ing behavior to jaw morphology. Materials and Methods Acute Mortality Monitoring for acute mortality occu rred in 1999 and 2003. Moribund red grouper (n=209) and red snapper (n=1,259) caught by hook and line during normal fishing trips aboard headboats fishing off Panama Cit y, Daytona and St. Augustine, Florida were collected, quantified, placed in ice slurries and transported in coolers to the laboratory for necropsy. Fishing occurred at depths ranging 10.4 to 42.7 m. In the laboratory all major body systems were examined for gross trauma and anomalies including the skin, eyes, fins, gills, heart, liver, spleen, swim bladder, stomach, and urinary bladder. Organ position within the body cavity was noted as well as any gross

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14 distortion or discoloration of organ tissues, ruptures or tear s in any tissues, presence of gas bubbles, or hemorrhaging. Trauma and a ny anomalies encountered were noted and documented using a Canon A20 digital still-camera. Based on necropsy findings, mortality was divided to thr ee categories; hook injury, barotr aumas, or “other” causes. The “other “category consisted of mortality caused by improper venting, stress, heat, or unknown causes when cause of death could not be ascertained. Latent Mortality Direct Observations Live specimens of red groupe r (n=46) and red snapper (n =241) were collected during some of the same fishing trips, transported to the laboratory and held for an observational period of up to one month to address latent fishing mortality. Upon arrival at the laboratory, before being released in holding ta nks, fish were placed into 114-liter coolers filled with freshwater treated with 30 drops of 10% buffered formalin for 10 minutes to kill parasites. Fish were removed from th e tanks, dipped a second time seven days later and transferred to new quarantine tanks. Fish were subjected to a third dip treatment before being placed in experimental tanks to kill any parasites that hatched from eggs not killed during previous treatments. The fres h dip “bath” water was removed from the coolers after each dip by opening the cooler drain and passing the water through a 202 mesh screen. Contents washed off the sc reen were collected, preserved and later examined under a dissecting microscope for parasites. Fish were kept in 3,406-liter tanks with a re-circulating filtrati on system. Filtration included mechanical (filter floss), chemical ( carbon), biological (flu idized bed), and

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15 ultraviolet (light) components. Water quality was strictly monitored daily to insure proper temperature, pH, salinit y, dissolved oxygen, ammonia, n itrate, nitrite, chlorine, and hardness were maintained. A YSI multi-probe monitor was used in conjunction with wet test kits to check water quality. Daily diet consisted of live shrimp and cut squid and/or fish. Fish were fed to satiety twice daily. A daily log of water quality, quantity of food consumed, fish condition, and any tank treatments such as partial water changes were noted. Fish Tagging Undersized red grouper and red snapper were caught using hook and line and tagged (red grouper: 1990-2007 and red snapper: 1999-2007 ) by Mote Marine Laboratory (MML) staff, student interns and volunteers, as well as by charter boat and headboat captains and crew, recreational, recreational-for-hire and commercial fishers throughout the eastern Gulf of Mexico and off the southeastern Flor ida coast (Figure 2-1). Tags and tagging kits, including instructions were provided Fishes were tagged using single-barbed Hallprint plastic dart tags inserted at an angle ne xt to the anterior por tion of the dorsal fin (Figure 2-2) Both large and small tags were used; tag size was determined by fish length.

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16 Figure 2-1. Tag and release sites for red grouper (Epinephalus morio) and red snapper (Lutjanus campechanus) Figure 2-2. Tagging an undersized red grouper prior to release. These tags had been used successfully in MML's Reef Fish Tagging Program. Data collected included tagging da te, gear type, tag number, time of day, bait used, water depth, fork length in inches, fish condition upon release, amount of time the fish was out

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17 of the water, whether or not fish were ve nted and the capture location to the nearest 1 degree of latitude and longitude. If fishes were vented before release, a fish venting tool was provided to volunteer fishers. Venting was accomplished by inserting the sharpened tube of a small diameter (e.g., 18gauge) needle at a 45 angl e through the body wall 2.5-5.1 cm from the base of the pectoral fin of the bloated fish. The venti ng tool was held in place until the majority of the expanded swim bladder gases were releas ed from the fish’s body cavity (Figure 2-3). Figure 2-3. Venting a red grouper. Tag information included tag number and the 1800 dedicated telephone number at Mote. The telephone was answered personally during work hours and calls regarding tag return information were recorded on weekends, holidays and evenings by an answering machine. Recapture data including tag number, date of capture, gear type, bait type, water depth, fork length in inches, capture location, ov erall condition of the fish and of the area around the tag insertion site and whether the fi sh was kept or releas ed, were recorded.

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18 Data were entered on a PC computer using Paradox software into a temporary file. Data entered into the temporary file were proofed by a second individual against the original data sheet. If no errors were detected, da ta were transferred electronically into the permanent reef fish database. To Increase Recapture Reporting a publicity campaign including MML press releases, presentations at scientific conferences and fishing club meetings and publication of information in various issues of a MARFIN funded Reef Fish Survival Study (RFSS) newsletter, were used to disseminate proj ect objectives and results. Copies of the newsletter were sent to all study participants as well as to fisheries scientists, fishery management agencies, industry representativ es, and newspaper “outdoor” writers and fishing magazine writers, who requested them. In addition, a tag lottery was held at the end of each year. The winning tag was chosen from all tags returned during that year. Both the tagger and the person returning the tag each received $100. A comparison of recapture rates for fish ca ught on circle versus J hooks was conducted to test two hypotheses. First, th at there would be no differen ce in recapture rates for red grouper caught on circle and J hooks and sec ond, that there would be no difference in recapture rates of red snapper caught by eith er hook type. Volunteer taggers from South Georgia to Texas were provided with 4/0 and 7/0 zero offset circle hooks either purchased or provided by Eagleclaw. Othe r participants supplied their own hooks. Only zero offset circle hooks were used becau se of reports of trauma inflicted by offset hooks (Prince et al. 2002). An attempt was made to obtain equal numbers of fish by

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19 treatment by sending a quarterly newsletter to participants publishing the number of fish tagged by hook type by depth. Recapture data for both species were compared by gear type at various depths and treatments (J vers us circle hook). Fish recaptures were used to estimate survival. Dentition and Jaw Lever Ratios Adult red grouper and red snapper carcasses we re obtained from comm ercial fish houses to describe dentition and collect jaw measurem ents to determine jaw lever ratios. Adult fish were used because jaws can change duri ng the juvenile stage. These measurements were used to mathematically describe the physical mechan ism responsible for observed feeding behavior. Fishes were measured to the nearest mm TL, FL and SL. Gape was measured (mm) in both species by pulling down on the lower jaw until the mouth was open to its maximum width without overexten sion and using calipers to measure the distance between the jaw joint and the attach ment of the adductor jaw muscles between the two coronoid processes on the jaw hinge. Jaws from adult red grouper (542-691 mm FL) and red snapper ( 510-870 mm FL) were prepared by dissecting the ma ndible bones from the head manually removing as much soft tissue as possible. The jaws were soaked in very hot, but not quite boiling water to soften residual tissue. Forceps were used to remove any remaining tissue. Jaws were then soaked in bleach water for an hour. Followi ng cleaning, jaws were dried for six hours at 49C in a drying oven to desiccate overlyi ng membranes to reveal tooth sockets. Mandibles were processed and tooth counts were made under a dissecting microscope following Weaver (2001).

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20 Closing and opening jaw lever ratios were cal culated following Wainwright and Richards (1995). The distance from the quadrato-mandi bular joint (QM), or jaw joint to the anterior edge of the dentary (the tip of the front tooth) was measured to determine mandible length which was used as the out-l ever measurement for estimating the lever ratios. The closing lever was then calculat ed as the ratio of the distance from the quadrato-mandibular joint (QM) to the inse rtion of the adductor mandibular muscle (AMM) divided by the out-lever distance. Closing in-lever = distance from QM to AMM Out-lever distance The opening in-lever was calcu lated by dividing the distance from the insertion of the interopercular ligament (IL) to the quadrato-m andibular joint by the out-lever distance. Opening in-lever = distance from QM to IL Out-lever distance Care was taken with each specimen to ensure m easurements were consistent, i.e. taken at the same location for each fish. Observations and comparisons of red grouper and red snapper jaw type (variation in mandible size and shape) and dentition were recorded. Location, size and type of teeth were noted. A Canon A20 digital still-camera was used to photograph the dentition of each species. Feeding Videos Healthy, laboratory acclimatized red groupe r (8 fishes/group) and red snapper (15 fishes/group) were filmed during feeding expe riments in separate 3,406 liter experimental tanks. Only fishes held in qua rantine tanks for at least a month and deemed healthy were

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21 used. Fishes were kept and tested in groups because captive red snapper remained healthier and acted normally when multiple fish were kept together rather than when kept alone (personal observation). Because unique numbers imprinted on fish tags were too small to be read while viewing the videos, i ndividual fish could not always be identified during the trials raising concerns of pse udo-replication (Hurlber t 1984, Machlis et al. 1985, Eberhardt and Thomas 1991). However, in an attempt to prevent pseudoreplication, individual ch aracteristics, such as small differences in fish size, color, and other physical characteristics (one fish had an enlarged eye), etc., were noted. For consistency 36 large bait shrimp were used during each multiple trial. Fishes were fed to satiety so even less aggressive fishes were filmed feeding. Of the 57 red grouper and 56 red snapper feeding sequences filmed only 14 red grouper a nd 25 red snapper sequences were complete and used because fish either swam out of the field of view before swallowing or other fish swam in front of the camera obstructing the view. Two cement blocks, the approximate size of the underwater camera housings, were positioned perpendicular to each other in the tanks and left overnight in the locations where the cameras were to be stationed. Th e next day, after fish had become accustomed to the cement blocks and ignored them, th e blocks were removed and replaced with a SeaViewer Sea Drop model 650 color camera (lateral orientation) and a Sony VX2000 camera in an Amphibico housing (head on orientation). Both cameras recorded concurrently and the video feed was viewed simultaneously out of sight of the fish on a laptop computer screen positioned away from the tanks. All video was recorded in miniDV format. To keep prey within the cameras’ fields of view, a live shrimp was tethered

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22 to a 1.8 kg diving weight with either 4 lb. monofilament or a rubber band. The weight with the attached shrimp was placed at the intersect point of the recording fields of the two submerged cameras. Color video of both species’ feeding behavi or was recorded. DVDs of the videos at normal feeding speed and slowed to 1/8 normal speed were made using Turtle Beach Video Advantage PCI model 1500-1 multi-media video capture software. Footage was used to determine feeding type. It should be noted that the obj ectives of these observations we re not to measure strike and prey capture kinematics, but ra ther establish feeding behavior type (ram feeding, suction, biting with oral manipulation, etc.) and determin e the length of time pr ey was kept in the mouth before swallowing. Prey residence time in the mouth was determined by counting the number of frames /sec (based on the esta blished time standard of 29 frames/sec) from prey capture to confirmed swallow while vi ewing the original videotape with Adobe Premiere Pro 2.0 software. Prey resi dence time was calculated by capturing and isolating each successful feeding sequence a nd subtracting the end sequence digital read out from the beginning read out. To provide a more accurate r eading, the last part of the read out (the number of fra mes/sec) was converted to the corresponding fraction of a second based on the 29 frames/sec standard. Only video segments of the entire sequence of capture to confirmed swallow were used. Video of prey capture but no visual swallow or no visual of initial prey capture before confirmed swallow was discarded. Data were entered into an Excel file and a t test, using Sigma stat for Windows version 3.5 software, was performed on the timed observation data of confirmed swallows to test the

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23 null hypothesis that there was no difference be tween the two species in the time prey remained in the mouth before swallowing. Results Acute Mortality During 1999 and 2003 when acute mortalities were noted and classifi ed, 191 mortalities were recorded during tagging tr ips. The 191 fish included 17 1 red snapper (13.6% of all red snapper caught during th is period and 20 red groupe r (9.6% of all red grouper captured during this period). Of 171 moribund red snapper collected, J hook damage was the leading source of acute mortality, respons ible for 49.1% of fatalities; more than double the J hook acute mortality rate (20%) for red grouper. Depth-related effects (barotraumas) accounted for 13.5% of red snapper mortality. No red grouper acute mortalities were attributed to depth-related e ffects as fish were caught at shallower depths than red snapper. Mortality in the “other” category cl aimed 37.4% and 80% of red snapper and red grouper, respectively. Base d on necropsy findings, acute mortality was divided into three categories; hook injury, barotrauma, or other causes. Hook injuries included lacerations to internal viscera, gills and/or the esophagus. In severe cases, organs were macerated. In all cases, blood lo ss was severe. Hook orientation played an important role in determining the site of internal injuries; if oriented upward when swallowed it punctured the aorta or other sect ions of the heart or severed major blood vessels serving the heart such as the duct of Cuvier (the anterior cardinal vein) (Figure 2-4); if oriented downward it t ypically punctured or destroyed the liver (Figure 2-5). Depth-related in juries were easily distinguis hed from hook injuries and

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24 Figure 2-5. Red snapper killed by J hook macerating the liver. Figure 2-6. Number of red grouper and red snapper acute shipboard mortalities partitioned by cause of death (depth-related, hooking, other ) 23 0 4 84 16 64 0 10 20 30 40 50 60 70 80 90 Red GrouperRed SnapperNumber of Fis h Depth Hook Other Figure 2-4. Red snapper killed by J hook trauma.

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25 included severe exophthalmia, visible gas bubbl es in the gills, visc era and blood vessels, and profuse hemorrhaging. Another key sign of barotrauma was stomach prolapse and extrusion through the oral cav ity, caused by the expansion of swim bladder gases. The “other” category included improper venting, stress, heat, or unknown causes as well as when no determinate cause of d eath could be found (Figure 2-6). Latent Mortality Similar to acute mortality rates, red sna pper deaths from latent hook mortality (29%) were much higher relative to red grouper (7%). Of undersized red snapper (n=241) caught on J hooks and transported to the laboratory from various fishing trips, 69 were dead upon arrival and 69 di ed in laboratory quaran tine tanks. Trauma was not immediately apparent in the 69 red snapper that died of latent hook mortality. These fishes appeared healthy during transport, ac ted normally, and fed well the first two days of captivity. On the third day of captivity, th ey lost their familiar bright red color and ceased feeding and swimming. Death occurred on day five. Necropsies revealed hook damage to vital organs, however, rather than a puncture that caused acute mortality, injuries occurred when a J hook nicked a small area of a vital organ (usually the heart or liver) and “drop by drop”, the fish slowly bled to death. Blood from the nicked organ pooled in the ventral coelom (Figure 2-7). Unlike the red sn apper, only three of the 45 live red grouper Figure 2-7. Pooled blood in a red snapper that died as a result of latent hook mortality.

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26 caught on J hooks died of similar injuries. The remainder of both species in the absence of hook damage (n=42 red grouper and n=103 re d snapper) not only survived, but grew and thrived during captivity. Another observation of red snapper late nt hook mortality was noted when a few emaciated pale sub-legal red snapper were caught during a fishing trip. Necropsies revealed these fish had been previously caught and the hook had longitudinally severed part of the esophagus resulting in the lower esophagus becoming a severed tube of necrotic tissue. Based on lack of blood and the state of the necrotic tissue damage, it was apparent the wound was not recent; however, no estimate of elapsed time between initial trauma and subsequent capture could be made Another indication that trauma was not recent was the emaciated condition of the fish in the absence of any apparent disease. Damage to the esophagus rendered these fish in capable of feeding as they were unable to swallow. Being caught again demonstrated th at although they still a ttempted to feed, the inability to swallow resulted in their emaciat ed condition and these fishes were in the process of eventually starving to death or becoming weakened easy prey for predators. Tag and Release and Circle versus J Hooks Between November 1, 2001 and September 30, 2007, red grouper (n=4,798) and red snapper (n=5,317) were tagged and released at depths ranging .5 m to 99 m. Most red grouper were caught at shallower depths ranging 12.5-21.3 m and 21.6 -30.5 m. Red snapper captures were more evenly spr ead over a broader depth range from 12.5-21.3 m21.6-30.5 m and 30.8-61.0 m. The majority of red snapper were tagged at 21.7-42.7 m, while most red grouper were caught between 10.4 and 21.3 m.

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27 Although more fish were tagged aboard headboa ts than recreational vessels, recapture data were lower from headboats than from the recreational fishing sector due to under reporting, rather than lack of recaptures. Only two headboat crews reported recaptures without direct assistance. Some fish tagged aboard headboats were recaptured in other sectors of the fishery. Some fish were originally caught on J hooks; others on circle hooks (Table 2-1). Of 3,935 red grouper tagged, the recap ture rate was 7.3% for J hooks versus 14.0% on circle hooks (Table 2-1; Figure 2-8). With twice as many recaptures of red grouper originally Table 2-1. Number of red grouper and red snapper tagged and recaptured by hook type. Species J hook tagged J hook recaps % J hook recaps Circle hook tagged Circle hook recaps % Circle hook recaps G test p values Red Grouper 3935 287 7.3 863 121 14.0 4.49 x 10-8 Red Snapper 2145 269 12.5 3172 258 8.1 2.3 x 10 -6

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28 Figure 2-8. Percent return of red grouper and red snapper recaptured by hook t yp e. Percent Return J vs. Circle Hooks 7.3 12.5 14.0 8.10.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 Red GrouperRed SnapperSpeciesPercent Return Rat e J Hooks Circle Hooks caught on circle hooks than on J hooks, red grou per clearly benefited from the use of circle hooks. Results of a log likeliho od G –test were highly significant ( p= 5.78 x 10-8) (Table 2-1). A log likelihood G-test for red snapper returns by hook type was also highly significant ( p= 2.34x 10-6), but contrasted with those for red grouper (Table 2-1). Red snapper originally caught on J hooks had a slightly better recapture rate that those initially caught on circle hooks (12.5% vs. 8.1%) (Table 2-1; Figure 2-8). Pooled data from the recreational-for-hire and recreational fishing sectors showed no benefits in using circle hooks for red snapper, in spite of 1,027 more red snap per being caught on circle hooks than on J hooks As one headboat tagged and recaptured a large number of red snapper, a G-test of circle versus J hook data restricted to recreationally caught red snapper was conducted. Results agreed with those reported for all fishing sectors combined; showing no benefit from using ci rcle hooks and increased survival from J hooked fish. Based on these results, both null h ypotheses were rejected. Red grouper clearly benefited from the use of circle hooks while red snapper recaptures revealed a slight increase in release su rvival of J hook captured fish.

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29 Red grouper and red snapper re turns by hook type and depth ( 27.4 m and > 27.4 m) showed that despite depth, ci rcle hooks continued to e nhance red grouper survival. Depth was a factor in red snapper hook recaptures. At shallow depths ( 27.4 m) there was only a slight difference in recaptures by hook type. At deeper depths (> 27.4m), twice as many red snapper originally caught on J hooks were recaptured (Table 2-2). Table 2-2. Red snapper recaptures by hook type and depth. Water Depth 27.4 m Hook Type Tagged Recaptured % Recaptured J 1,660 220 13.3 Circle 1,437 185 12.9 Water Depth > 27.4 m J 585 49 8.4 Circle 1,765 71 4.0 Dentition and Jaw Lever Ratios Red grouper averaged 526 teeth in the upper ja w and 201 in the lower jaw (Table 2-3). Although tooth size was small, rows of small teeth occur on the top and bottom premaxilla, with some pointed inward ( Figures 2-9 and 2-10). Red grouper also possess canine like teeth located on the frontal marg in of the red grouper upper and lower premaxilla (Figures 2-11 and 2-12). They had a larger gape than red snapper at equal body size for all fish measured (Figure 2-13).

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30 Table 2-3. Red grouper specimen lengths, gape size and upper and lower jaw tooth counts. Fish FL (mm) TL (mm) SL (mm) Gape (mm) Upper Jaw Lower Jaw Count Ca nin e Outer Edge Total Count Can ine Outer Edge Total RG1 635 662 560 69.38 407 2 31 440 142 2 46 190 RG2 615 646 544 78.80 597 2 32 631 166 3 54 223 RG3 623 654 550 72.90 478 2 29 509 132 2 44 178 RG4 630 660 559 79.95 357 2 35 394 150 2 48 200 RG5 656 685 578 68.85 493 2 36 531 177 2 44 223 RG6 600 629 530 78.65 386 2 30 418 154 2 42 198 RG7 600 632 526 73.05 373 2 31 406 140 2 58 200 RG8 691 723 601 77.80 334 2 28 364 168 2 53 223 RG9 646 677 562 64.15 560 2 37 599 137 2 44 183 RG1 0 542 570 485 72.30 431 2 39 472 132 2 53 187 Table 2-4. Red snapper specimen lengths, gape size and upper and lower jaw tooth counts. Fish FL (mm) TL (mm) SL (mm) Gape (mm) Upper Jaw Lower Jaw Count Canin e Outer Edge Total Count Canin e Outer Edge Total RS1 640 683 565 59.20 587 1+2 25 615 79F 0 30 109 RS2 543 581 474 47.55 479 1+2 20 502 43F 0 24 67 RS3 645 680 563 56.10 585 1+2 24 612 57F 0 33 90 RS4 870 928 760 77.10 869 1+2 21 893 52F 0 24 98 RS5 510 548 450 50.95 419 1+2 23 445 70F 0 28 98 RS6 725 780 625 64.30 624 1+2 25 652 63F 0 31 94 RS7 819 881 727 80.60 712 1+2 21 736 53F 0 31 84 RS8 618 665 558 55.50 615 1+2 24 642 96F 0 26 122 RS9 555 594 488 50.65 560 1+2 23 586 84F 0 32 116 RS10 550 591 478 52.50 535 1+2 20 558 64F 0 33 97 RS11 654 705 565 56.70 645 1+2 21 669 35F 0 28 63 RS12 637 683 556 58.75 563 1+2 26 592 59F 0 26 85 RS13 589 630 510 52.55 478 1+2 25 506 55F 0 25 80

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31 Figure 2-9. Multiple rows of small backward pointing teeth in red grouper top pre-maxilla. Figure 2-10. Lower jaw dentition of red grouper showing inward pointing teeth.

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32 Red snapper dentition consisted of approximately 616 teeth in the upper jaw and 93 teeth in the lower mandible (Figures 2-14 through 217). A set of large canine teeth was present in the upper mandible but absent in the lower jaw (Figures 2-16 and 2-17). Red snapper top canine, top fused and depressible tooth length was longer than those of red grouper (Figure 2-16 and 2-18). There were a reduced number of teeth in the red snapper bottom jaw (Figure 2-17) and a greater space between bottom teeth in red snapper than those of red grouper (Figure 2-12). Gape was smaller for red snapper than red grouper at comparable sizes (Table 2-4). Figure 2-12. Red grouper front lower dentition featuring canines. Figure 2-11. Red grouper front upper dentition featuring canines. Size reference: each square = 5 mm x 5 mm.

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33 Figure 2-16. Lateral view of red snapper upper jaw showing canines and conical teet h Figure 2-13. Red grouper upper canines and large gape. Figure 2 14. Rows of sharp conical teeth in both the red snapper upper and lower jaws. Figure 2-15. Red snapper upper canine teeth.

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34 Figure 2-17. Red snapper lower jaw frontal view showing the reduced number of conical shaped teeth in the lower mandible. Figure 2-18. Lateral view of red grouper upper jaw showing canines and conical teeth.

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35 Red grouper jaw lever ratios (0.17 closing/0. 24 opening), were hi gh. Red snapper jaw lever ratios were also high (0.32 closing/0.22 opening). Although both species had high jaw lever ratios, mandibular shape varied betw een the two species. The rear margin of the red grouper dentary was greatly extended because of the increased height of the ascending process and an extension of the post erioventral region crea ting a wide mandible The red snapper ascending process was shorter and narrower (Figur es 2-19 and 2-20). Figure 2-20. Lateral view of red grouper lower jaw. Yellow arrowshowslocationofascendingprocess. Figure 2-19 Lateral view of red snapper lower jaw. Yellow arrow shows location of ascending process.

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36 Feeding Videos Although both red grouper and red snapper were aggressive feeders, taped footage of the two species revealed marked differences in feeding behavior. Differences included the manner prey was approached, captured and consumed. Since the objective was to understand the effect feeding had on hook mort ality, only observations of predator orientation, prey capture, and time prey rema ined in the mouth before swallowing were recorded. Species differed in the manner prey was a pproached. All red groupe r in the tank showed interest in prey when introdu ced but dominant fish (lighter colored fish) fed first and often guarded prey preventing those lower wi thin the hierarchy from feeding. To circumvent this, dominant red grouper were segregated from lowe r ranking individuals after they fed to allow all fish in the tank to be filmed while feeding. Unlike the hierarchal feeding seen in red grouper, when prey was in troduced into the tank, red snapper formed together in a tight school hesitating to appro ach the introduced prey until one fish began to approach the prey, at wh ich point all fish swam toward the prey. Video analyses revealed red grouper were ambush suction fe eders. They approached prey, examined it and then enveloped it by expanding their large buccal cavity (Figure 2-21). Prey was or ally manipulated (mouthed) a nd swallowed whole. Unlike red snapper, which immediately swam away from the prey capture site following prey acquisition, red grouper either remained at the site or slowly swam away mouthing captured prey. Other red grouper would attempt to steal an expelled shrimp or scan the

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37 immediate area for additional prey, but unlike red snapper, never tried to remove prey from the successful grouper’s mouth. At times tethered shrimp were expelled from the grouper’s mouth because the fish’s teeth did not sever the monofilament tether. In these instances, expelled shrimp were observed to be alive, completely unharmed, and if not for the tether, capable of escape indicating oral teeth were not involved in prey processing. However expelled shrimp were recaptured by ei ther the original fish or by a nearby fish, especially if the other fish was of higher rank. Red snapper exhibited biting feeding behavior, approaching prey via high velocity lunges with open mouths using their canine teeth to sever the monofilament tether and bite the prey (tethered shrimp), often severing the shrimp into two Figure 2-22. Red snapper exhibiting biting feeding behavior caught in the process of biting a shrimp in half before swallowing it. Figure 2-21. Red grouper exhibiting ram suction feeding. Note full buccal extension as the entire shrimp is drawn into the fish’s mouth.

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38 parts (Figure 2-22). When this occurred, the first snapper took part of the prey; a second immediately took what remained of the shrimp carapace. Other red snapper tried to steal any piece of the prey protruding from the succ essful fish’s mouth. This observation explained the behavior that immediately following prey acq uisition, the successful fish swam away to escape surrounding conspecifics that mobbed it, trying to st eal prey from its mouth. On average, red snapper handled prey far le ss time than red grouper (red snapper x=3.74 seconds, red grouper x=6.62 seconds) (Figure 2-23). The null hypothesis that there was no difference between the two species in prey residence time within the mouth before swallowing was rejected (p<0.001). Data passed the normality test (p=0.157) and the equal variance test (p=0.489). The difference was-2.373 and t = -4.339 with 37 degrees of freedom (p=< 0.001) with a 95% confidence interval for difference of means: -3.481 to -1.265. Figure 2-23. Difference in prey residence time in the fish’s mouth before swallowing between red snapper and red g rou p er. Red SnapperRed Grouper 0 2 4 6 8 10 Median ( ) 75th 25th 10th 90th Percentiles: Mean ( )...__

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39 Discussion Acute Mortality Red grouper did not show the severe obvious si gns of hook mortality seen in red snapper. Necropsies of acute mortalities caught fr om headboats showed hook trauma was the leading cause of death for red snapper. Red snapper mortalities were highest at depths ranging 27.7-42.7 m (depth range where most fish were captured); however hook trauma not barotraumas caused most mo rtality (49.1%). Overall, hoo king injuries were found to account for the largest overall percentage of red snapper mortalities. Comparing overall mortality rates between species showed 64.3% of the total red sna pper catch died from hook trauma, almost double the 35.7% of red gr ouper that succumbed to hook mortality. It appears hooking injuries are far more co mmon and harmful to red snapper than red grouper at depths ranging 27.7-42.7 m and that hooks have a much larger impact on red snapper survival than depth related effect s at these depths. Circle Hooks Although circle hooks have become popular and are perceived by many to be an effective tool in significantly reducing hook mortality in all species, results from numerous hook survival studies are mixed showing some speci es benefit greatly from circle hooks, some moderately, while others show no survival difference between J and circle hooks and for a few species circle hooks have been shown to be detrimental (Cooke et al. 2003a, Cooke et al. 2003b, Cooke et al. 2003c, Cooke and Suski 2004). Some of the species which greatly benefit from being ca ught on circle hooks include juve nile bluefin tuna, striped bass, Atlantic and Pacific sailfish, yellowfin tuna, and Pacific halibut (Falterman and Graves 2002, Lukacovic and Uphoff 2002, Prince et al. 2002, Skomal et al. 2002,

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40 Trumble et al. 2002). Red grouper also be nefited from circle hooks based on higher recapture rates. However, red snapper re sults agree with those of Zimmerman and Bochenek (2002) and Malchoff et al. ( 2002), for summer flounde r, who reported that circle hooks were not more effective than J hooks in reducing hooking mortality. Rather, more red snapper originally captured on J hooks were recaptured. Cooke and Suski (2004) wrote “Though much of the current literature shows the benefits from using circle hooks, the data are some what limited, and, in many cases, are somewhat conflicting”. Although their meta-ana lysis results demonstrated, circle hooks reduced hooking mortality rates by roughly 50% versus J hooks for some species; they also reported that circle hooks were responsible for increa sed tissue damage in others. Circle hooks vary by whether or not the hook is offset and by the degree of offset. Malchoff et al. (2002) reporte d “hook offset may have negated the normal jaw hooking only pattern” typically observed with circle hooks. This is corroborated in the sailfish fishery where highly offset circle hooks were associated with significantly more deep hooking than minor offset (4%) and non-offset hooks (Prince et al. 2002). Although zero offset circle hooks were used in this study, there was a differen ce in survival in favor of J hooks for red snapper caught at shallow depths where barotrauma was not a factor. Red snapper appear to be one of the species, like summer flounder, where circle hooks do not provide increased survival over J hooks (Jon Lucy, Vi rginia Institute of Marine Science, personal communication); desp ite J hooks being the leadi ng cause of red snapper mortality as determined by necropsy.

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41 Dentition and Jaw Lever Ratios Dentition differed dramatically between th e two species as did variations in jaw morphology reflecting important differences in feeding methodologies. Prey type, disposition and feeding behavi or are consistent with fish dentition and jaw morphology (Mullaney and Gale 1966, Wainwright and Richards 1995, Hernandez and Motta 1997, Porter and Motta 2004, Ward-Campbell and Beamish 2005) For example, Wainwright (1991) found that morphology could be used to predict comparative prey shell crushing ability in labrids. Red grouper teeth were small and consisted of ro ws of teeth in the dentary and premaxilla that were caudally rotated, indicating these inward pointing teeth are used for grasping and holding during initial prey ca pture rather than piercing or slashing prey thus serving to prevent captured prey from escape before swallowing. Red grouper use their oral jaws for initial prey capture and their pharyng eal jaws for prey processing which are swallowed whole (Burns and Pa rnell in prep.). Stomach co ntents of wild caught red grouper showed most prey was swallowed whole but somewhat macerated. Adult red grouper feed on many different sp ecies of fishes and octopods as well as a variety of crustaceans, including portunid, and Callapa crabs, shrimps, stomatopods, and palinurid and scyllarid lobsters (GMFMC 1981b). W eaver (1996) found crustaceans dominate the juvenile red grouper diet, while the adult red grouper diet cons ists of 50% fishes and 50% crustaceans.

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42 The red snapper diet differs markedly from th at of red grouper. Red snapper have larger teeth in both mandibles and fe wer fixed teeth in the lower mandible. Many piscivorus species frequently have large te eth in the upper jaw and fewer fixed teeth in the lower jaw (Weaver 2000). This tooth spacing in the lo wer mandible strengthens tooth penetration into soft bodied prey. Although shrimp are the most common prey of juveniles, red snapper become more piscivorus after age one Adult red snapper are characterized, as carnivores since their usual prey are fish and squid (GMFMC 1981b). According to Weaver (2001), increased tooth size, fewer teeth, probably increase capture success of elusive, soft-bodied prey, especi ally, fishes and squid as soft -bodied prey require less oral manipulation than those with hard shells or a carapace. Stomach content analyses of hook-and-line caught wild red snapper, revealed that although some food (small prey) was swallowed whole, there were often pieces of prey in red snapper stomachs. These results are in keeping with observed rapid lung ing at prey and the us e of canine teeth for slashing and biting prey, captu red on the feeding videos. Wainwright et al. (2001) repor ted on variation of prey appr oach by a variety of cichlid species as a result of differ ences in feeding behavior. Th is agrees with laboratory observations of taped red snapper and red gr ouper feeding behavior. Red snapper fed as a school with several individuals rapidly appr oaching a single prey item simultaneously. Their large canines were used to slash prey that was quickly swallowed. Often prey was cut in half by the first snapper to reach it leaving the remainder to be snapped up by a conspecific. Unlike the ra pid lunging and biting behavior observed during red snapper feeding, red grouper acted indi vidually and exhibited sucti on feeding behavior appearing

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43 to examine the shrimp before creating a str ong suction force to draw it into the mouth by extending its large bucc al cavity and completely engulfing prey. The teleost jaw operates as a system of tw o opposite lever devices one for opening; the other for closing the mouth (Wainwright and Richards 1995, Westneat 1995). Mandibular dimensions and the associated bi omechanical properties they determine have been studied for other fish taxa (Wainw right and Richards 1995, Westneat 1995, Albertson et al. 2005, Huber et al. 2005). Results show jaw shape is a major factor in determining biomechanical processes that gove rn a species’ jaw func tioning and feeding behavior. Lower jaw depression begins bucca l expansion responsible for prey capture. A high lever closing ratio transl ates into decreased velocity of jaw opening but increased jaw strength. A high lever opening represents increased velocity (Wainwright and Richards 1995). Jaw level ratios were relati vely high for both species but ratios showed they represented two feeding types. Red grouper are suction feed ers; red snapper are biters. As suction feeders, red grouper draw prey into their mouths via hydraulic pressure produced by buccal cavity expansion and th e simultaneous expulsion of water through the opercula. The production of hydraulic pr essure requires impr essive jaw strength (Wainwright and Richards 1995, Westneat 1995). However with a lever ratio of 0.17 closing/0.24 opening, red grouper have jaws strong enough for suction feeding, but with a capacity for greater velocity for jaw opening and closing required for producing a rapid increase of buccal cavity volume while e xpelling water through the operculum to

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44 forcefully draw in entire prey. Red sna pper (biters) have a ja w lever ratio of 0.32 closing/0.22 opening. The 0.32 cl osing ratio translates into greater biting force necessary for deep penetration of the large sharp canin es in the upper jaw to grip and immobilize prey combined with the fewer farther spaced teeth in the lo wer jaw that enhances tooth penetration to bite prey into pieces easily (Weaver 2000). Mandibular shape also varied between the two species. The rear margin of the red grouper dentary was greatly expanded through th e height of the ascending process and an expansion of the posterioventral region cr eating a wide mandible. The longer the ascending process the greater the increase in added force transmitted to the jaw by the mandibular muscle (Wainwright a nd Richards 1995, Weaver 2000). Feeding Videos Different feeding behavior pr edicated on dentition and ja w ecomorphology appears to be a major factor responsible fo r differences in hook mortalit y between red grouper and red snapper. Although both species ar e aggressive feeders, vide o showed not only a marked difference in feeding behavior but also differe nt prey residence times within the mouth. This is not unexpected as red grouper draw entire prey into thei r mouths and orally manipulate “mouth” it, before swallowing it whole whereas red sna pper quickly caught, bit and swallowed pieces or small entire prey. Fish Ecomorphology and Hooks The divergent patterns seen in red grouper a nd red snapper dentiti on, jaw shape and the other morphological features determining feed ing behavior appear to provide insights

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45 into factors responsible for J and circle hook mortality. How these species approach wild prey appears to parallel the manner in whic h they deal with bait on J and circle hooks. Although both are predators, red grouper and red snapper have evolved to fill different ecological niches feeding on dissimilar prey. Fishing with J hooks requires the angler to set the hook. Based on this premise, longer pr ey residence time within the oral area, allows more time for an angler to set a J hook before bait is swallowed. Red snapper, with a briefer prey residence time in the mouth before swallowing exhibited far higher acute and latent J hook mortalit y than red grouper that ke pt prey in the mouth and pharynx longer to orally manipulate it before swallowing. Red grouper use their oral jaws for initial prey capture and their pharyngeal jaws for prey processing (Burns and Parnell in prep.). It is during prey processing by the pharyngeal jaws that the angler feels the pressure or tug on the line and sets the J hook. Setting the J hook during prey processing in the pharyngeal jaws jerks the baited hook out of the pharyngeal ja ws where it becomes lodged in the mouth or jaw. This proce ss would explain the observed reduced hook mortality found for red grouper (B urns and Parnell in prep.). Following this reasoning, red snapper, with a smaller prey residence time in the mouth, should have higher J hook mortal ity than red grouper. Once red snapper bite, prey are rapidly swallowed quickly pa ssing through the pharyngeal jaws that are covered with sharp, fragile, canine teeth that serve to keep prey moving down the esophagus (Burns and Parnell in prep.). This modification of the pharyngeal jaws prevents prey or hooks from easily exiting them and reversing move ment toward the mout h (Burns and Parnell in prep.). Tugging on the fishing line would mo re often result in gut hooked fish or other

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46 serious lacerating trauma to the esophagus, pharyngeal jaws and potentially the heart, liver or other internal organs (Burns and Parnell in prep.). Th is feeding mode appears to be occurring in situ because red snapper necropsy result s of acute and latent mortalities caused by J hooks are consistent with injuries caused by J hooks bei ng set while or after the fish swallowed the hook. Fish feeding behavior based on ecomor phology may govern not only differences in J hook mortality but also the disparity with which species benefit from circle hooks. Study results comparing hook mortality among gag, scamp and red porgy (Overton and Zabawski 2003) showed a 24% J hook rele ase mortality for ga g and scamp, both picivores as adults, (Randa ll and Bishop 1967, Weaver 1996, 2000) versus 5% for red porgy, that feed primarily on inverteb rates (Randall and Bishop 1967, Manooch 1977, Castriota et al. 2005). Gag recapture result s by hook type in the MML database closely resembled those for red snapper (13.1% on J hooks and 9.9% on circle hooks; G test: p=0.036939). Since both species share simila r dentition and diet s (Weaver 2001), this may explain J and circle hook results for thes e species were analogous but very different from red grouper results based on the ecomorphology. Additional research on various species is needed to confirm that J and circle hook mortality is heavily dependent on ecomor phology and fish behavior rather than phylogeny. Variation resulting from ontogenetic and inter-specific differences in jaw strength and velocity may be species specifi c as species within the same family can occupy diverse niches as a result of differe ntiation in dentition and jaw lever ratios,

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47 leading to different feeding behavior. It may be that ecomorphology can be applied to traditional fishery management tools used to develop models to predict hook mortality susceptibility and determine the level of bene fit a species would derive from the use of circle hooks and J hooks. Regulations used to manage fisheries are commonly applied to multi-species complexes and while beneficial to some species these regulations may either have no effect or be detrimental to others. However, ecomorphology could be a useful tool in ecomanagement not only in understanding how fishing affects a fish species’ ecology, but by providi ng insights into predicting ho ok mortality estimates for other species commonly caught in the fishery. While MPAs are an important part of environmental management, insight into mor phological features speci es have evolved to adapt to their ecolo gical niches in the marine environment may allow for the development of methodologies to enhance surv ival by the ability to develop predictive models of mortality by hook type and provide new manage ment strategies for these species in fished areas. References Cited Albin, D. and K.A. Karpov. 1998. Mortality of lingcod, Ophinodon elongatus, related to capture by hook and line. Marine Fisheries Review 60(3):29-34. Ayvazian, S.G., B.S. Wise and G.C. Young. 2002. Short-term hooking mo rtality of tailor (Pomatomus saltatrix) in Western Australia and the impact on yield per recruit. Fisheries Research 58:241-248. Bacheler, N.M. and J.A. Buckel. 2004. Does hook type influence the catch rate, size, and injury of grouper in a North Carolina commercial fishery? Fisheries Research 69:303-311. Bettoli, P.W. and R.S. Osborne. 1998. Hooking mortality and behavior of striped bass following catch and release angling. North American Journal of Fisheries Management 18:609-615.

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48 Bettoli, P.W., C.S. Vandergoot and P.T. Ho rner. 2000. Hooking mortal ity of saugers in the Tennessee River. North American Fisheries Management 20:833-837. Bartholomew, A. and J.A. Bohnsack. 2005. A review of catch-and-release angling mortality with implications for no-take reserves. Reviews in Fish Biology and Fisheries 15:129-154. Bendock, T. and M. Alexandersdottir. 1993. Hooking mortality of Chinook salmon released in the Kenai River, Alaska. North American Journal of Fisheries Management 13:540-549. Bohnsack, J.A. 2000. A comparison of the shortterm impacts of no-take marine reserves and minimum size limits. Bulletin of Marine Science 66:635-650. Burns, K.M., C.C. Koenig, and F.C. Coleman. 2002. Evaluation of multiple factors involved in release mortality of undersi zed red grouper, gag, red snapper, and vermilion snapper. Mote Marine Labora tory Technical Report No. 814. (MARFIN grant # NA87FF0421). Burns, K.M., N.F. Parnell and R.R. Wilson. 2004. Partitioning release mortality in undersized red snapper bycatch: comparison of depth vs. hooking effects. Mote Marine Laboratory Technical Report No. 932. 36 p. Burns, K.M., N.J. Brown-Peterson, R.M. Ov erstreet, J.G. Gannon, J.M. Sprinkel, B.D. Robbins, and C.A. Weaver. 2006. Geogr aphic comparison of age, growth, reproduction, movement, and survival of red snapper off the state of Florida. Mote Marine Laboratory Technical Report No. 1147. Burns, K.M. and N.F. Parnell. In prep Comparison of hook mortality between red snapper, Lutjanus campechanus, and red grouper, Epinephalus morio, in the eastern Gulf of Mexico and Atlantic Ocean off Florida, with emphasis on differences in feeding behavior and jaw morphology. Castriota, L., Finoia M.G. and F. Anda loro. 2005. Trophic interactions between Xyrichtys novacula (Labridae) and juvenile Pagrus pagrus (Sparidae) in the central Mediterranean Sea. Electronic Journal of Ichthyology 2:54 -60. Chopin, F.S., T. Arimoto and Y. Inoue. 1996. A comparison of the stress response and mortality of sea bream Pagrus major captured by hook and line and trammel net. Fisheries Research 28:277-289. Clifton, K.F. and P.J. Motta. 1998. Feed ing morphology, diet, and ecomorphological relationships among five Caribbean labrids (Labridae, Teleostei). Copeia 1998:953-966.

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49 Coleman, F.C., W.F. Figueira, J.S. Uela nd and L.B. Crowder. 2004. The impact of United States recreational fisher ies on marine fish populations. Science 305(5692):1958-1959. Cooke, S.J., B.L. Barthel and C.D. Suski. 2003a. Effects of hook type on injury and capture efficiency of rock bass, Ambloplites rupestris, angled in south-eastern Ontario. Fisheries Management and Ecology 10:269-271. Cooke, S.J., C.D. Suski, B.L. Barthel, K.G. Ostrand, B.L. Tufts and D P. Philipp. 2003b. Injury and mortality induced by four hook types on bluegill and pumpkinseed. North American Journal of Fisheries Management 23:883-893. Cooke, S.J., C.D. Suski, M.J. Siepker and K.G. Ostrand. 2003c. Injury rates, hooking efficiency and mortality pot ential of largemouth bass (Micropterus salmoides) captured on circle hooks and octopus hooks. Fisheries Review 61:135-144. Cooke, S.J., and I.G. Cowx. 2004. The role of recreational fishing in global fish crises. BioScience 54(9):857-859. Cooke, S.J. and C.D. Suski. 2004. Are circle hooks an effective tool for conserving marine and freshwater recreationa l catch-and-release fisheries? Aquatic Conservation: Marine and Freshwater Ecosystems 14:1-28. Cooke, S.J. and C.D. Suski. 2005. Do we need species-specific guidelines for catch-andrelease recreational angling to effectivel y conserve diverse fi shery resources? Biodiversity and Conservation 14:1195-1209. Davis, M.W. and B.L. Olla. 2001. Stress and de layed mortality induced in Pacific halibut by exposure to hooking, net to wing, elevated seawater temperature and air: implications for management of bycatch. North American Journal of Fisheries Management 21:725-732. Dextrase, A.J. and H.E. Ball 1991. Hooking mortality of la ke trout angled through the ice. North American Journal of Fisheries Management 11:477-479. Diggles, B.K. and I. Ernst. 1997. Hooking mortal ity of two species of shallow-water reef fish caught by recreatio nal angling methods. Marine Freshwater Research 48:479-483. Doi, T., T. Nakamura, M. Yokota, T. Maruya ma, S. Watanabe, H. Noguchi, Y. Sano and T. Fujita. 2004. Hooking mortality and grow th of caught and released Japanese charr Salvelinus leucomaenis and masu salmon Oncorhynchus masou masou in experiment ponds. Nippon Suisan Gakkaishi 70(5):706-713.

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50 Dubois, R.B., T.L. Margenau, R.S. Stewar t, P.K. Cunningham and P.W. Rasmussen. 1994. Hooking mortality of norther n pike angled through ice. North American Journal of Fisheries Management 14:769-775. Eberhardt, L.L. and J.M. Thomas. 1991. Designing environmental field studies. Ecological Monographs 6(1):53-73. Falterman, B. and J.E. Graves. 2002. A Preliminary Comparison of the Relative Mortality and Hooking Efficiency of Circle and Straight Shank (“J”) Hooks Used in the Pelagic Longline Industry. p. 80-87. In: Lucy, J.A. and A.L. Studholme (eds.). Catch and release in marine recreational fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland. Gitschlag, G.R. and M.L. Renaud. 1994. Fi eld experiments on survival rates of cages and released red snapper. North American Journal of Fisheries Management 14:131-136. GMFC (Gulf of Mexico Fishery Management Council). 1981b. Amen dment to the Reef Fish Fishery Management Plan, Gulf of Mexico Fishery Management Council, 2203 N. Lois Avenue, Suite 1100, Tampa, Florida 33607. Hernandez, P. and P.J. Motta. 1997. Trophic co nsequences of differential performance: ontogeny of oral jawcrushing performance in the sheepshead, Archosargus probatocephalus (Teleostei, Sparidae). Journal of Zoology (London) 243:737-756. Huber, D.R., Eason, T.G., Hueter, R.E., and P. J. Motta. 2005. Analysis of bite force and mechanical design of the feeding mechanism of the durophagous shark Heterodontus francisci. Journal of Expe rimental Biology 208:3553-3571. Hurlbert, S.H. 1984. Pseudoreplication and the design of ecological field experiments. Ecological Monographs 54(2):187-211. Julliard, R., N.C. Stenseth, J. Gjster, K. Lekve, J. Fromentin and D.S. Danielssen. 2001. Natural mortality and fishing mortality in a co astal cod and population: a release-recapture experiment. Ecological Applications 11(2):540-558. Kwak, T.J. and M.G. Henry. 1995. Largemout h bass mortality and related causal factors during live-release fishing tourna ments on a large Minnesota lake. North American Journal of Fisheries Management 15:621-630. Lee, W.C. and E.P. Bergersen. 1996. Infl uence of thermal and oxygen stratification on lake trout hooking mortality. North American Journal of Fisheries Management 16:175-181.

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51 Lindsay, R.B., R.K. Schroeder and K. R. Kenaston. 2004. Hooking Mortality by anatomical location and its use in esti mating mortality of spring Chinook salmon caught and released in a river sport fishery. North American Journal of Fisheries Management 24:367-378. Lucy, J.A. and M.D. Arendt. 2002. ShortTerm Hook Release Mortality in Chesapeake Bay’s Recreational Tautog Fishery. p. 114-117. In: Lucy, J.A. and A.L. Studholme (eds.). Catch and Release in Marine Recreational Fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland. Lukacovic, R. and J.H. Uphoff. 2002. Hook Location, Fish Size, and Season as Factors Influencing Catch-and-Rel ease Mortality of Striped Bass Caught with Bait in Chesapeake Bay. p. 97-100. In: Lucy, J.A. and A.L. Studholme (eds.). Catch and Release in Marine Recreational Fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland. Machlis, L., P.W.D. Dodd and J.C. Fentress 1985. The pooling fallacy: problems arising when individuals contribute more than one observation to the data set. Zeitschrift fr Tierpsycologie 68 : 201-214. Malchoff, M.H. and S.W. Heins. 1997. Shor t-term hooking mortality of weakfish caught on single-barb hooks. North American Journal of Fisheries Management 17:477-481. Malchoff, M.H., J. Gearhart, J. Lucy and P. J. Sullivan. 2002. The Influence of Hook Type, Hook Wound Location, and Other Variab les Associated with Post Catch-andRelease Mortality in the U. S. Summer Flounder Recreationa l Fishery. p. 101-105. In: Lucy, J.A. and A.L. Studholme (eds.). Catch and Release in Marine Recreational Fisheries. American Fisheries Societ y, Symposium 30, Bethesda, Maryland. Manooch, III, C.S. 1977. Foods of the red porgy, Pagrus pagrus Linnaeus (Pisces: Sparidae), from North Caro lina and South Carolina. Bulletin of Marine Science 27(4):776-787. Millard, M.J., S.A. Welsh, J.W. Fletcher, J. Mohler, A. Kahnle and K. Hattala. 2003. Mortality associated with catch and release of stripe d bass in the Hudson River. Fisheries Management and Ecology 10:295-300. Motta, P.J. 1984. Mechanics and functions of jaw protrusion in tele ost fishes: a review. Copiea 1984(1):1-17. Mullaney, Jr., M.D. and L.D. Gale. 1966. Ecomorphological relati onships in ontogeny: anatomy and diet in gag, Mycteroperca microlepis (Pisces: Serranidae). Copeia 1:167-180.

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52 Murphy, M.D., R.F. Heagey, V.H. Neugeba uer, M.D. Gordon and J.L. Hintz. 1995. Mortality of spotted seatrout released from gill-net or hook-and-line gear in Florida. North American Journal of Fisheries Management 15:748-753. Neal, J.W. and D. Lopez-Clayton. 2001. Mo rtality of largemouth bass during catch-andrelease tournaments in a Puerto Rico reservoir. North American Journal of Fisheries Management 21:834-842. Nelson, K.L. 1998. Catch-and-release mortality of striped bass in the Roanoke River, North Carolina. North American Journal of Fisheries Management 18:25-30. Overton, A.S. and J. Zabawski. 2003. Releas e mortality of Unders ized Fish from the Snapper/Grouper Complex odd the North Ca rolina Coast. Final Report to North Carolina Sea Grant Fisheries Resources Grant Program 03-FEG-21 18 p. Porter, H.T. and P.J. Motta. 2004. A compar ison of strike and prey capture kinematics of three species of pisciv orous fishes: Florida gar (Lepisosteus platyrhincus), redfin needlefish (Strongylura notata), and great barracuda (Sphyraena barracuda). Marine Biology 145:989-1000. Prince, E.D., M. Ortiz, and A. Venizelos. 2002. A Comparison of Circle Hook and “J” Hook Performance in Recreational Catch-andRelease Fisheries for Billfish. p. 6679. In: Lucy, J.A. and A.L. Studholme (eds.) Catch and Release in Marine Recreational Fisheries. American Fisheries Societ y, Symposium 30, Bethesda, Maryland. Randall, J.E. and B.P. Bishop. 1967. Food ha bits of reef fishes of the West Indies. Studies in Tropical Oceanography (Miami). 5:665-847. Render, J.H. and C.A. Wilson. 1994. Hook-andline mortality of caught and release red snapper around oil and gas plat form structural habitat. Bulletin of Marine Science 55:1106-1111. Schirripa, M.J. and K.M. Burns. 1998. Growth estimates for three species of reef fish species in the eastern Gulf of Mexico. Bulletin of Marine Science 61:581-591. Schirripa, M.J,, K. Burns and J.A. Bohnsack. 1993. Reef fish rele ase survival based on tag and recovery data. SEFC, Miami Laboratory, Contribut ion No. MIA 92/93, 34 p. Skomal, G.B., B.C. Chase and E.D. Prince. 2002. A Comparison of Circle Hook and Straight Hook Performance in Recreational Fisheries for Juvenile Atlantic Bluefin Tuna. 2002. p. 57-65. In: Lucy, J.A. and A.L. Studholme (eds.). Catch and Release in Marine Recreational Fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland.

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53 Systat Software Inc. 2004. Sigm aplot version8.02a. Richmond, CA Trumble, R.J. and S.M. Kai mmer, and G.H. Williams. 2002. Review of the Methods Used to Estimate, Reduce, and Manage Bycat ch Mortality of Pacific Halibut in the Commercial Longline Groundfish Fisheries of the Northeast Pacific. p. 88-96 In: Lucy, J.A. and A.L. Studholme (eds.). Catch and Release in Marine Recreational Fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland. Wainwright, P.C. 1991. Ecom orphology: experimental functi onal anatomy for ecological problems. American Zoologist 31(4):680-693. Wainwright, P.C. and B.A. Richards. 1995. Predicting patt erns of prey use from morphology of fishes. Environmental Biology of Fish 44:97-113. Wainwright, P.C., L.A. Ferry-Graham, L.A., T.B. Waltzek, A.M. Carroll, C.D. Hulsey, and J.R. Grubich. 2001. Evaluating the us e of ram and suction during prey capture by cichlid fishes. Journal of Experimental Biology 204(Pt 17):3039-3051. Ward-Campbell, B.M.S. and F.W.H. Beamish. 2005. Ontogenetic changes in morphology and diet in the snakehead, Channa limbata, a predatory fish in western Thailand. Environmental Biology of Fishes 72:251-257. Weaver, D.C. 1996. Feeding ecology and eco morphology of three sea basses (Pisces: Serranidae) in the Gulf of Mexico. Ma ster’s Thesis. University of Florida, Gainesville, Florida. Weaver, D.C. 2001. Feeding ecology and f unctional morphology of western Atlantic groupers (Serranidae: Epinephe linae). Proceedings of the 9th International Coral Reef Symposium, Bali, Indonesia. 8 p. Westneat, M.W. 1995. Phylogenetic system atics and biomechanics in ecomorphology. Environmental Biology of Fishes 44:263-283. Westneat, M.W. 2003. A biomechanical mode l for analysis of muscle force, power output and lower jaw motion in fishes. Journal of Theoretical Biology 223:269-281. Westneat, M.W., M.E. Alfaro, P.C. Wainwr ight, D.R. Bellwood, J.R. Grubich, J.L. Fessler, K.D. Clements and L.L. Smith 2005. Local phylogenetic divergence and global evolutionary converge nce of skull function in r eef fishes of the family Labridae. Proceedings of the Royal Society B 272:993-1000. Wilde, G.R., M.I. Muoneke, P.W. Bettoli, K.L. Nelson and B.T. Hysmith. 2000. Bait and temperature effects on striped bass mortality in freshwater. North American Journal of Fisheries Management 20:810-815.

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54 Wilson, R.R. and K.M. Burns. 1996. Potent ial survival of rel eased groupers caught deeper than 40 m based on shipboard and in situ observations, and tag-recapture data. Bulletin of Marine Science 5(1):234-247. Zar, J.H. 1999. Biostatistical Analysis. 4thedition. Prentice Hall, New Jersey. Zimmerman, S.R. and E.A. Bochenek. 2002. Evaluation of the Effectiveness of Circle Hooks in New Jersey’s Recreational Su mmer Flounder Fishery. p. 106-109. In: Lucy, J.A. and A.L. Studholme (eds.). Catch and Release in Marine Recreational Fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland.

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55 Chapter Three: Differences between Red Grouper ( Epinephelus morio ) and Red Snapper ( Lutjanus campechanus ) Swim Bladder Morphology and How These Differences Affect Survival dur ing Rapid Depressurization Abstract Depth induced mortality caused by trauma during rapid decompression acutely impacts survival of undersized reef fish discarded in compliance with minimum size regulations (Render and Wilson 1994, Gitschlag and Renaud 1994, Render and Wilson 1996, Collins et al. 1999). Although red grouper and red snapper suffered injuries caused by rapid decompression, mortality varied between species based on anatomy, physiology, and behavior. If not allowed to return to depth immediately, red grouper (Epinephelus morio) died from rapid decompression at sh allower depths than red snapper (Lutjanus campechanus). Although Wilson and Bu rns (1996) have shown red grouper, gag, and scamp can potentially survive decompression in sufficient numbers to justify a minimum size rule if fish are rapidly allowed to return to the corres ponding habitat depth, differences in morphology influence survival This study tested multiple hypotheses which included: 1) red grouper were more su sceptible to depth-i nduced mortality than red snapper at shallower dept hs, based on swim bladder size, thickness, and number and arrangement of rete mirabile and gas gland ce lls within the swim bladder; 2) smaller red grouper (< 30.5 cm) survive rapid decompressi on better than larger (> 38 cm) fish based on changes in swim bladder structure with fi sh length between 30.5-38 cm; 3) venting red grouper and red snapper is harmful to fish a nd does not enhance fish survival; 4) that

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56 there is no difference in survival by gear type ; 5) ascent rate does not affect red grouper survival from depth in fish traps, and 6) that in addition to pressure changes, other factors influence fish survival during rapid decompre ssion. Objectives were accomplished by combining morphological and hi stological examinations to assess the gene ral appearance of swim bladders, gas glands, rete mirable, and comparison of tissue hemorrhages from necropsies of red grouper and red snapper acute mortalities fr om fish caught off headboats. Results were compared with data from laboratory depth simulation experiments in fish hyperbaric chambers, a fi sh tagging study using tag returns as a proxy for survival and examining red grouper caught by commercial long-lines and fish traps. Red grouper had larger (in relation to body size), thinner swim bladders than red snapper. Red snapper swim bladder ruptures were smal ler than those of red grouper. Red grouper > 38.1 cm FL had developed a star-shaped ar ea of tissue on the posterior swim bladder ventral wall, absent in red sn apper that incorporated some rete and a greater number of gas gland cells that aid in gas absorption and secretion. Beginning va scularization in this area was first visible under a dissecting microscope when red grouper length reached 31.8 cm Overall red snapper survived rapid decompression better than red grouper because of a smaller quantity of gas in the swim bladder and less tendency to hemorrhage, especially in smaller fish. Swim bladders of both red grouper and red snapper ruptured with rapid pressure changes of 1 atm of pressure (10 m). In the laboratory both red grouper and red snapper easily survived rapid decompression from 21 m; however, 50% of red grouper suffered tr auma at 27.4 m; red snapper did not. Differences in ability to tole rate rapid decompression increased with depth. Red snapper (40%) suffered mortality or sub-lethal eff ects during rapid decompression from 42.7 m.;

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57 the remainder survived at 1 atm pressure. At the same depth red grouper mortality (75%) was much higher. At 61 m, 45% of red snappe r died, but vented red snapper survived at 1 atm of pressure when vented. Red groupe r never survived rapid decompression from 61 m to 1 atm pressure for more than 30 minutes, even when vented because emboli developed when fish could not return to simu lated depths in holding tanks (Burns et al. 2004). Results of these investigations were compared with data from red grouper and red snapper fish tagging studies. Red grouper and red snapper caught off Florida were quantified and measured and tagged and rel eased from recreational-for-hire, private recreational and commercial vessels by Mote Marine Laboratory (MML) staff, student interns, and volunteer taggers. At sea, red grouper survival from this depth and deeper occurred only if red grouper im mediately returned to habita t depth. This difference in survival demonstrates that morphological and physiological differences between the two species described in this chapte r determine the ability to adjust to rapid depressurization. Some red grouper caught on commer cial long-line gear, tagged, released and vented were recaptured up to 2,172 days of freedom. Red grouper caught in commercial fish traps at depths of 61 m were less likely to suffer severely ruptured sw im bladders. Swim bladders were intact and inflated or if rupt ured, swim bladders had a smaller linear or pinhole wound rather than the large swim bladder rupture found on red grouper caught on hooks at any depth. Some trap-caught red grouper did not show the common external symptoms of rapid depressuri zation. However, necropsies revealed some fish with damaged swim bladders did have gases escap e into the body cavity and exhibited torqued internal organs.

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58 Introduction Trauma resulting from swim bladder ruptur e caused by rapid decompression from depth during fishing is a major factor contributing to mortality for physocli stic fishes (Burns and Restrepo 2002, Burns et al. 2004, Collins et al. 1999, Koenig 2001, Marshall 1970, Wilson and Burns 1996). The extent of internal trauma is depth dependent and intensifies as pressure increases. Internal trauma is characterized by external symptoms including stomach prolapse, exophthalmia, in testine prolapse and body bloating. Body bloating results in inability to return to habitat depth sinc e fish are unable to control buoyancy. Floating at the surface, fish are subject to predation by seabirds, marine mammals and predatory fishes and are exposed to the elements. This highly visible loss of discarded live fish has been the source of mu ch debate by fishers, scientists and fishery managers both nationally and inte rnationally. Various techni ques, such as fish venting (removing swim bladder gases from the fish ’s body cavity) and th e rapid release rig (attaching a lead weight and a barbless hook upside down to fishing line, hooking the fish’s jaw with the inverted barbless hook and quickly transpor ting the fish to the bottom) are just two methods used to return fish to habitat depth (Queensland FMA 1989, Collins et al. 1999, Burns 2001a, Shipp 2001, Burns and Restrepo 2002, Burns et al. 2004, Theberge and Parker 2005). It was unknown if these techni ques were merely cosmetic and sank fish or if they improved survival. Other unknowns included the fate of fishes with ruptured swim bladders, if a ruptured swim bladder healed healing duration, if swim bladder rupture caused the same amount of trauma in all species critical survival de pths and effects of

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59 different gear types. Answers to these que stions are critical because swim bladder rupture occurs with a ch ange of 1 atm (10 m) and trauma intensity increases with depth. Although some fishing occurs at 10 m, most takes place at much deeper depths and fishers must comply with the minimum size law that mandates all undersized fishes must be returned to the water, rega rdless of condition. To be eff ective, a substantial portion of released fish must survive. This regulation has created an enormous national catch and release program whose merits continue to be debated (B artholomew and Bohnsack 2005, Rummer and Bennett 2005, Wilde 2009). Investigations comparing survival of red grouper and red snapper at va rious depths and under a va riety of conditions were conducted to address the efficacy of this regulat ion with regard to effects of barotraumas on these species. Results are provided in this chapter. Like most marine teleosts, re d grouper and red snapper have physoclistic (closed) swim bladders. Causes and implications of dept h induced trauma in these two species were investigated using various me thodologies including comparisons of acute mortality, swim bladder gross morphology a nd histology, laboratory dept h simulations using fish hyperbaric chambers, a tag and release study in the eastern Gulf of Mexico and the South Atlantic off the state of Florid a, a small fish trap study cond ucted in the eastern Gulf of Mexico and necropsies of commerci al trap caught red grouper. Investigation of how fishing g ear and practices affect the fi sh swim bladder requires an understanding of swim bladder elements and th eir role in the norma l functioning of the swim bladder operating under hom eostatic conditions. The f unction and features of this

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60 hydrostatic organ have been described by various fish physiologists (Jones and Marshall 1953, Fange 1966, Marshall 1970, Pelster 1997). Morphologically, the fish swim bladder can be described as a gas-filled, ellipsoid sac located in the upper body cavity below the backbone and kidneys th at develops as an outgrowth of the roof of the foregut. It is defined as open or physostome, if the link (pneumatic duct) with the foregut remains in adult fish. However, most (at least two-thirds) teleost swim bladders are closed (physoclistic). In some, the pneumatic duct is only present during larval stages, used to fill the developing swim bladder with swallowed air before it degenerates. In others, gas is formed by gas gland cells within the swim bladder (Marshall 1970). The fish swim bladder evolved early and was common in many ancient fishes. Some ancient tassel-fins may have used them as a buoyant scuba tank as do modern lung-fishes that collect and store air swallowed at the su rface. Although some te leosts, also utilize their swim bladders for sound production or as a hydrophone through connections with the ears, its main function is that of a hydros tatic organ. Some fishes, such as sharks, rays, mackerel and cobia lack swim bladders however for those species which have them, they conserve energy and allow the fish to rema in neutrally buoyant with little effort even while stationary. To provide neutral buoyancy sw im bladder capacity of marine fish must be approximately 5% of its body volume (M arshall 1970). A marine species’ swim bladder must not only be kept inflated at 5% of the fish’s body volume but at a pressure equal to that of the surrounding water. Swim bladder volume follows Boyle’s law making pr essure and volume changes wi th changes in hydrostatic

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61 pressure. Pressure at the water’s surface is 1 atm and increases by 1 atm, or 14.7 pounds per square inch, per each 10 meters of descen t. A fish swimming near the surface is only subject to the pressure of 1 atm. At 10 meters the pressure increases to 2 atm, compressing the swim bladder to half its original surface volume. The fish becomes heavier than water allowing descent. To return to the surface and retain neutral buoyancy, the swim bladder must be inflated to its original volume, because returning to the surface decreases pressure in the swim bladder by half. The swim bladder expands as pressure decreases therefore the fish must deflate it to prevent over buoyancy inhibiting controlled movement (Marshall 1970). Physostomes can quickly deflate their swim bladders by removing swim bladder gases during ascent by releasing gas through the pneumatic duct as bubbl es through the mouth or gills. Physoclists are incapable of rapi d deflation. They rely on diffusion of swim bladder gases via a dense network of bundles of arterial and ve nous blood capillaries called rete mirable housed with in the swim bladder walls. They adjust resorption or secretion as needed. Swim bladder gases, often nitrogen, oxyge n and carbon dioxide, diffuse into the rete as long as gas pressure wi thin the swim bladder is greater than that in the capillary blood. Although difference in ga s pressure varies with water depth, deflation rate is proportional to the area and complexity of the rete and to circulation speed. In many physoclists, gas absorption occurs in the oval, a dist inct thin-walled area on the dorsal wall of the swim bladder that is in contact with the rete. The oval contains circular and radial muscles th at open and close it. Contr action and expansion of these

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62 muscles, which are under neural control, either expose or limit rete contact with the swim bladder gases. Although some physostomes can rapidly inflate their swim bladders, within one to two hours, by swallowing air forced down the pneum atic duct into the sw im bladder, most physostomes and all physoclists obtain gases needed for swim bladder inflation through the gills and inflate the swim bladder by a slower method via gas secretion through gas gland cells that receive gas vi a the blood through the rete mirab ile. This close association between gas gland cells and rete (Figure 3-1) is essential for swim bladder gas production not only to create gas pressures required to inflate the swim bladder but also to maintain gases within it. The tightly packed arterial and venous capillary bundles that compose the rete mirable system are arranged para llel to each other in a countercurrent arrangement providing an extensive contac t surface area for gas exchange between arterial (ingoing) and venous (outgoing) capillaries that tr ansport blood to and from the gas gland. In the absence of this count er current, the swim bladder would lose gas through outgoing blood flow. This loss would not only prevent gas pressure ma intenance but also inhibit Figure 3-1. Illustration of the close association of the gas glands (gg) and the rete mirable (rm) in the red grouper swim bladder ventral wall.

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63 swim bladder inflation because each of the swim bladder gases must be produced at a pressure greater than that already within the swim bladder. To infl ate the swim bladder, the rete and gas glands must produce gas pressures at concen trations individually greater than the combined pressure of the gases with in the swim bladder. Since the combined pressure of gases dissolved in water is equa l at most to 1 atm increased pressure is achieved through a counter-current multiplication of gas retrieved from venous flow and carried back to the gas gland via the arterial capillaries ensuring the pressure of any gas eventually becomes greater th an the combined pressure of the gases within the swim bladder. To concentrate gases from the outgoing venous blood in the rete, the gas gland produces acidic metabolites, including lactic acid a nd carbon dioxide. Thes e acidic metabolites reduce gas solubility in the venous capill aries and release some of the oxygen bound to hemoglobin. This increases gas pressure in the venous blood wher e it becomes greater than that in the arterial blood. This extra pressure results in gas diffusion from venous to arterial capillaries transporting gas to the gas gland, where it is concentrated and multiplied. Gas deposition and secretion maintain the swim bladder at proper buoyancy keeping the fish neutrally buoyant. Both processes are und er neural control as the swim bladder is innervated by the autonomic nervous syst em through branches of the vagus nerves. Excitation of appropriate nerves results in the correct response of gas deposition or secretion. However, fish w ith closed swim bladders, brought to the surface from depth

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64 during fishing, are unable to decompress ra pidly enough to compensate for the fast pressure changes responsible fo r swim bladder rupture. When the swim bladder ruptures, swim bladde r gases are immediately released into the fish’s body cavity causing internal trauma. Trauma severity is dependent upon the quantity of gas released (depth dependent) a nd fish physiology. External signs of trauma include various degrees of body bloating, stomach prolapse, exophthalmia, gill hemorrhage and intestine protrusion from the anus. There is much debate if fishes survived this trauma and what the lasting effects might be for survivors. Like most marine teleosts, red grouper and red snapper have physoclistic (closed) swim bladders. Causes and implications of depth induced trau ma in these two species were investigated by approaching the problem using various me thodologies including co mparisons of acute mortality, swim bladder gross morphology a nd histology, laborator y depth simulations using fish hyperbaric chambers, a tag and release study and comparison of gear types (hook-and-line, commercial l ong-line and commercial reef fish traps). Six hypotheses were tested. They included 1) red groupe r are more susceptible to depth-induced mortality than red snapper based not only on sw im bladder size and thickness, but also on the number and arrangement of bundles of re te mirable and gas gland cells within the swim bladder; 2) smaller red grouper (< 30.5 cm) survive rapid decompression better than larger (> 38 cm) red grouper because of changes in swim bladde r structure with size (between 30.5-38 cm); 3) venting red grouper and red snapper is harmful to fish and does not enhance fish survival; 4) survival rates for fish caught at the same water depth were unaffected by gear type; 5) ascent rate does not affect survival from depth in fish traps,

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65 and 6) other factors in addition to pressure changes infl uence fish survival during rapid decompression. Methods Acute Mortality Moribund red grouper and red snapper caught on hook-and-line that were landed dead or died on deck during normal fishing trips aboa rd headboats fishing off Panama City, St. Petersburg, Sarasota, Venice, Ft. Myers, Daytona and St. A ugustine, Florida and the Dry Tortugas, were collected, quantified, placed in ice slurries and transported in coolers to the laboratory for necropsy. In the laboratory all major body systems were examined for gross trauma and anomalies includ ing the skin, eyes, fins, gills, heart, liver, spleen, swim bladder, stomach, and urinary bladder. Fish were also checked for any changes in the position of organs within the body cavity, gross distortion, discol oration, ruptur es or tears in any tissues, presence of gas bubbles, or hemorrhaging. Trauma and any anomalies encountered were documented using a Canon A20 digital still-cam era. Mortality was divided to three categories ba sed on necropsy findings: hook injury, barotraumas, or “other” causes. The “other” category consiste d of mortality caused by improper venting, stress, heat, or unknown causes when cause of death could not be ascertained. Swim Bladder Differences Swim Bladder Collection and Processing: To collect information on swim bladder structur e, a relatively small number of fish were selected spanning the size ra nge (under permitted trips wh ere fish could be retained regardless of size). Upon arrival at the laborat ory, specimens were logged in to continue

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66 documenting chain of custody. Fish were measured and examined for external and internal signs of barotraumas, disease or abnormalities. Swim bladders were examined for inflation or rupture and to assess the general appearance of the bladder before measurement to determine the approximate size ratio of red grouper and red snapper swim bladders in relation to fish length. Excised fresh swim bladders were fixed, preserved in 10% formalin and placed into labeled jars. Swim bladder gross morphology was examined under a dissecting microscope and a comparison made between the two species. Sections of the swim bladder we re embedded in paraffin, sectioned at 4 micrometers and stained in hema toxylin and eosin to examine gas glands, rete mirabile and any hemorrhaging. Intact ruptured and hist ological sections were examined and photographed. Swim bladder and trip data were entered on a PC computer using Excel spreadsheets. Laboratory Simulations of Depth Eff ects Using Fish Hyperbaric Chambers Live Fish Collection and Fish Sanitation Protocol Before experiments were conducted, red sna pper were brought into the laboratory to determine water quality parameters necessary to maintain excellent health over time. Red snapper not maintained under the strictest wa ter filtration and wate r quality protocols were prone to parasite infestat ion, disease and ill health ir regardless of fish density and fish care. When tested in the hyperbaric cham bers fish not maintained under very strict sanitation protocols sustained more sever inju ries and fewer fish survived. To ensure healthy fish, seawater was s ubjected to numerous filtrations Seawater brought in through intake pipes in Sarasota Bay passed through a course sand filter on its way to ozination

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67 and storage. From the stor age tanks, water was passed th rough a fine sand filter, biological filter, fluidized be d and finally through UV light filtration before reaching tanks. Each tank was its own system (each tank had its own biological filter, fluidized bed and 4-bulb UV light filter) and isolated from all other tanks. All equipment associated with each tank (nets used to add or remove fish, beakers to collect water quality, etc.) were labeled and us ed exclusively for that tank. Undersized red grouper and re d snapper were captured by hookand-line aboard headboats and held in 208-liter coolers or in shipboard live wells. Fish were transported to the laboratory in 946-lite r tanks equipped with oxygen a nd kept at capture water temperatures. Upon arrival, fish were pl aced in other 208-liter coolers for a 5-minute freshwater dip treated with Formalin soluti on (2 drops 37% Formalin/3.8 liters of water) to remove ectoparasites and gill trematodes. Fish were also dipped 7, 14 and 21 days after the first dip treatment to kill any ectoparasites that hatched after the first dip. Fish received a final dip, on day 28, before be ing transferred from quarantine tanks to experimental holding tanks. Following each dip, dip water was filtered through a 202 mesh sieve. Sieve contents were collected and viewed under a disse cting microscope to identify any parasites. Fish were quarantined for one month to identify any health or parasite problems, to eliminate the possi bility of complicatio ns from latent hook mortality, and to acclimate fish to handli ng and laboratory surroundi ngs. Fish were fed chunks of fresh fish and live shrimp daily un til all fishes were sated. Food quantities were monitored. Tanks and filters for each tank were cleaned and water chemistry

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68 checked daily. Following quarantine, fishes were divided into di fferent experimental groups and well fed before being placed in the hyperbaric chambers. Laboratory Pressure Experiments Year 1 Hyperbaric chambers (described in Wilson and Burns 1996, shown as Figure 3-2), were used to produce laboratory simulations of pressure cha nges red grouper and red snapper would experience during capture from de pths of 21.3, 27.4, 42.7 and 61.0 m (31 psi, 40 psi, 63 psi and 90 psi, respectively). Depths were c hosen to match important capture depths in the fish tagging study. Four ch ambers were used simultaneously, providing four replicate samples. After fish were ac climated to conditions within the chamber, observations of gauge pressure and fish beha vior/orientation within each chamber were made and recorded every 30 minutes. Observa tions of fish behavior were made through an acrylic view plate (Figure 3-3). Acclimation was confirmed when fish became neutrally buoyant and achieved an upright (vertic al) orientation within the chamber Figure 3-2. Series of fish hyperbaric pressure chambers situated over a 1,000 l tank, used in the pressure simulation experiments

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69 following initial tendency to list or lie on its si de at the bottom of the chamber. Pressure within the chambers was increased in a step-wise manner until experimental depth simulation was achieved. When acclimation wa s confirmed, hydrostatic pressure within the chamber was rapidly decreased (rate approx. 2-3 m/sec to ambient at 1 atm), whereupon the fish was removed from the cham ber as quickly as possible. During the first year, all chambers were depressurized simultaneously. During year two, each chamber was depressurized individually so fish in each chamber were unaffected by pressure changes occurring in another cham ber during recompression. A stopwatch was used to time handling time for each fish and all times were recorded. Timing began when the pressure gauge reached 0 psi (1 atm ambient) and ended when the fish was released from the chamber. Upon removal from the chamber, fish were vented and released into holding tanks. Immediately following venting, one fish from each experiment was anesthetized with Figure 3-3. Red grouper in one of the fish hyperbaric chambers as observed through the acrylic view plate. Ta gs with unique numbers identified each experimental fish.

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70 MS222, sacrificed and necropsied to determine the extent of internal trauma sustained from that depth simulation. The remaining fish were released into holding tanks to heal. A second fish was sacrificed 2-4 days after being removed from the chamber and a third after seven days to document healing. During year two, the fourth experimental fish was kept for long-term (1-2 months) observation. After all experiments were completed, this last group of fish was divided by species. The red grouper were sent to the Florida Aquarium in Tampa and the re d snapper were moved to the large exhibit tank at Mote Aquarium. All major body systems were examined dur ing necropsy for any gross trauma or anomalies that could have been caused by ra pid depressurization. The skin, eyes, fins gills, heart, liver, spleen, sw im bladder, stomach and urinary bladder of each fish were examined. Observations included organ pos ition within the body cav ity, gross distortion or discoloration of organ ti ssues, gas bubbles, ruptures or tears in any tissues and hemorrhaging. A digital still-camera was us ed to document any trauma and anomalies found. Year 2 During the second year, an addi tional pressure experiment us ing the hyperbaric chambers was conducted to examine fish acclimation times during controlled ascents from simulated depths of 21.3, 27.4 and 42.7 m. Red grouper and red snapper were acclimated to depth as in all other expe riments; however, depressurizatio n was initiated in stepwise increments allowing the fish to acclimate to each new depth (pressure) before continuing the next incremental decrease in pressure. Chamber pressure was decreased gradually

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71 until the fish exhibited sympto ms of depth related stress, such as increased buoyancy, downward oriented swimming, or bloating, at which time th e amount of pressure within the chamber was maintained. The psi on the pressure gauge was recorded at each stopping point. Fish remained at this stoppi ng point until acclimation was affirmed when the fish exhibited neutral buoyancy. Once neutral buoyancy was achieved, psi within the chamber was decreased further until outward symptoms of depth related stress again manifested. Fish were then held at this new pressure until acclimation was confirmed. This stepwise decrease in chamber pressure car ried out in increments continued until fish were at ambient pressure (1 atm) at which point, fish were removed from the chambers. Acclimation times were recorded. Necropsie s were performed using the same schedule as above to determine if any trauma took place during controlled ascents. Fish Tag and Release Fish Tagging Undersized red grouper and red snapper were tagged by MML staff, student interns and volunteers, as well as by charter boat and headboat captains and crew, private recreational and commercial fi shers throughout the eastern Gulf of Mexico and off the southeastern Florida coast (F igure 3-4). Undersized red grouper were also tagged and released by MML staff and a trai ned observer in the southeaste rn Gulf of Mexico, aboard various commercial reef fish long-line vessels out of Madiera Beach, Florida. Tags and tagging kits including instructions were provided to all.

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72 All fish were tagged usi ng single-barbed Hallprint plastic dart tags inserted at an angle next to the anterior portion of the dorsal fin. Both large and small tags (for juveniles) were employed. These tags have already been used successfully in MML's Reef Fish Tagging Program. Data collected included ta gging date, gear type tag number, time of day, bait used, water depth, fork length in inches (converted to metric in the lab for analyses), fish condition upon release, amount of time the fish was out of the water, whether or not fish were vented and the cap ture location to the nearest one degree of latitude and longitude. To determine if fish venting was harmful tw o treatments were employed. 1) Over a 10year period (1997-2007), Mote st aff, student interns and vol unteers aboard recreationalfor-hire and private recreational vessels released captured tagg ed fish; 2) the other half were also vented before release. Venting instructions were provi ded in tagging kits, in Florida Sea Grant brochures, in copies of newsletters provided to fishers and through a Mote website video produced to teach proper venting techniques. Half of the captured Figure 3-4. Study area where red grouper and red snapper were tagged.

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73 fish were tagged and released, th e other half were also vented before release. If fishes were vented before release, a fish venting tool was provided to volunteer fishers. Venting was accomplished by inserting the sharpened tu be of a small diameter (e.g., 18-gauge) needle at a 45 angle through the body wall 2.55.1 cm from the base of the pectoral fin of the bloated fish. The ven ting tool was held in place unti l most of the expanded swim bladder gases were released from the fi sh’s body cavity. Fish were subject to both treatments regardless of depth. In deeper wa ters (> 27 m) fishes were vented to test venting as a tool to enhance su rvival from barotrauma. In shallow waters (< 21 m) fishes were vented to determine if venting in a nd of itself was hazardous to fish health, by introducing pathogens into the fish’s body from the venting t ool or by causing damage to internal organs. Tag information included tag number and the 1-800 toll-free dedi cated telephone number at Mote. The telephone was answered pers onally during work hours and calls regarding tag return information were recorded on weekends, holidays and evenings by the answering machine. Return data including tag number date of capture, gear type, bait type, water depth, fork length in inches, capture locat ion, overall fish condition and of the area around the tag insertion site and whether the fish was kept or released were recorded Data were entered on a PC computer using Paradox software into a temporar y file. A second individual proofed the entered data against the original da ta sheet. If no errors were detected, data were transferred electronically into the perm anent reef fish database. Recapture data for

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74 both species were compared by gear type at va rious depths and treatments (vented vs. not vented). Fish recaptures were used to estimate survival. Evaluation of survivorship was accomplished by comparing study results with thos e of other Mote studies, as well as by integrating the new data into MML's ongoing long term reef fish tagging program (discussion in Schirripa et al. 1993, Wilson and Burns 1996), as these data have proven very reliable (Schirripa and Burns 1998). To increase recapture reporting a public ity campaign including MML press releases, presentations at scientific conferences and fishing club meetings and publication of information in various issues of a MARFIN funded Reef Fish Survival Study (RFSS) newsletter, were used to disseminate projec t objectives and results. Copies of the newsletter were sent to all study participants as well as to fisher ies scientists, fishery management agencies, industry representati ves, and newspaper “Outdoor” writers and fishing magazine writers, who re quested them. In addition, a tag lottery was held at the end of each year. The winning tag was chosen from all tags returned during that year. Both the tagger and the person returning the tag each received $100 funded by MARFIN projects. Fish Trap Study Six commercial reef fish tr aps were deployed during two o ffshore fishing trips off the commercial long-line vessel Bold Venture out of Madiera Beach, Fl orida to compare trap

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75 caught fish condition with fishes caught on comm ercial long-line at comparable depths as part of CRP Project # NA03NMF 4540417. To determine if trap ascent rate affected survival of commercial trap caught fish, two treatments were employed. Traps were deployed off a commercial long -line vessel and afte r a 4-hour soak time (at one station soak time was 14 hours due to weather conditions ), were hauled to the surface either by hand or by the winch used to deploy and retrieve the long-line cable Trap recovery by treatment alternated among traps. If the first trap was haul ed to the surface by hand, the second was retrieved by winch. Ascent rates for both treatments at all depths fished were timed with a stopwatch and recorded. Data we re entered into an Ex cel spreadsheet after the trip. Six study sites were chosen based on wate r depth and because red grouper had been captured at these locations previously during re gular long-line fishing trips (Figure 3-5). Site coordinates were recorded to the n earest 1-minute of latit ude and longitude to prevent reporting exact fishing locations. Traps were baited with mackerel and squid and fished for four hours with the exception of one site that was fished for 14 hours due to weather. Six sites were fished using multiple traps (5-6 pe r site). Site depths ranged 52.4-115.8 m. Fish behavior during trap retrieval was filmed by sliding a SeaViewer underwater color camera with a 46 m video cable down the buoy lin e so fish within the trap could be videotaped during ascent. The camera cable was attached to a shipboard SonyGV-D 900 digital video recorder to pr ovide real time viewing of trap ascent, allowing for

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76 observation of behavior and condition of captured fish wi thin the traps. As traps were hauled to the surface, video data were stampe d with the time, date, and GPS coordinates. After traps were recovered, filming focuse d on the fish within the recovered traps on Figure 3-5. Fish trap study sites. Water depths are in meters. Distance is in km.

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77 deck and after their removal from the traps. All fish caught were identified, counted and their condition noted. Most fish, regardless of condition, were released with release condition (swam straight down, swam down slow ly or floated) noted. Only red grouper were tagged with Hallprint plastic dart tags before releas e. A few red grouper specimens were kept to determine the condition of the swim bladder and internal organs. No red snapper were caught in the traps. Red Grouper Purchased from Commercial Fish Trappers Ten legal sized red grouper were purchased from commercial fish trappers (depths ranging 55-61 m) to determine if these co mmercially caught fishes showed common external and/or internal symptoms of ra pid depressurization and to compare fish condition caught by commercial fi sh trappers during a normal fishing trip and fish caught during the previously describe d fish trap experiment. Necr opsies were conducted because commercial trap fishers asserted that most red grouper caught in trap s, even at deeper depths (62 m) survive and show little or no external signs of depth-induced trauma, including swim bla dder rupture. Since fish are normally landed gutted, fish purchased were landed whole by special agreement with the captain. The agreement st ated that the purchased grouper were not only to be whole, but were to be the last fishes caught before re turning to the dock; ensuring fish were as fresh as possible. Commercially caught red grouper were brought back to the laboratory in a cooler filled with ice slurry, examined for any outward appearance of depth-induced in juries and photographed. Follo wing external examination,

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78 fish were necropsied to detect any signs of trauma to internal organs. Photos of internal organs were taken during necropsy. Results Swim Bladder Differences Gross Anatomy Swim bladders from more than 140 red gr ouper (20.5-76.6 cm FL) and 62 red snapper (12.3-67.4 cm FL) caught on hook-and-line off headboats were examined. Red grouper possess a more capacious (in relation to tota l body size) swim bla dder than red snapper and thus the capacity to contain a larger volume of swim bladder gases than red snapper (Figures 3-7 and 3-8). Red grouper swim bl adder tissue was thinner than that of red snapper and red grouper swim bladder ruptures were always much larger (approximately 1/3- the length of the swim bladder) than those in red snapper for hook-and-line caught fish (Figures 3-9 and 3-10). Red grouper were prone to bi -lateral cranial hemorrhagi ng from escaped swim bladder gases that traveled to the head and both eyes if fish are unable to reacclimate to depth rapidly (Figure 3-11). In contrast, red snapper did not show the same proclivity to cranial hemorrhaging as red grouper follow ing rapid decompre ssion at depths 62 m, especially when vented. During laboratory depth si mulations, some red snapper experienced exopthalmia in one or both eyes at 42 m a nd deeper but in all these fishes, the brain appeared unaffected. Fishes with one eye a ffected remained with the rest of the school and acted and fed normally in holding tanks. In the holding tanks, bl ind red snapper were able to maintain upright orie ntation, detect food, feed a nd respond to sounds indicating

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79 Figure 3-6. Acute shipboard mortality partitioned by cause of death (depth-related, hooking, other). Figure 3-7. Inflated red grouper swim bladder showing swim bladder size in proportion to total body size. Shipboard Acute Mortality 23 0 4 84 16 64 0 10 20 30 40 50 60 70 80 90 Red GrouperRed Snapper Depth Hook OtherNumber of Fish

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80 Figure 3-8. Inflated red snapper swim bladder showing swim bladder size in proportion to total body size. Figure 3-9. Initial rupture in a red grouper swim bladder.

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81 Figure 3-10. Initial rupture in a red snapper swim bladder. Figure 3-11. Bilateral post-cranial hemorrhages in red grouper rapidly decompressed from 21.3 m.

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82 normal brain function. These fishes surviv ed for months and had to be humanely euthanized at the end of the study. Although rete mirable and gas glands respons ible for gas absorp tion, secretion and resorption were located in the inner ventral wall of the anterior portion of the swim bladder of both species, size a nd shape of this anterior gas co ntrolling portion of the swim bladder differed. In additi on, 71 out of 140 red grouper were > 38.0 cm FL and all had a secondarily less vascularized star-shaped area on the posterior ventral wall of the swim bladder visible with a dissecting microsc ope absent in red snapper of any size (Figure 3-12). Under a dissecti ng microscope, this posterior area also appeared absent in small (< 30.5 cm FL) red grouper. Figure 3-12. Inner view of the ventral wall of a red snapper and red grouper swim bladder showing the differences in areas of gas absorption and resorption and the secondary structure in the red g rou p er p osterior p ortion of the swim bladder.

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83 Laboratory Simulations of Depth Eff ects Using Fish Hyperbaric Chambers Barotrauma Effects of Rapid Decompression from Simulated Depths In depth simulation experiments red grouper ex hibited higher suscepti bility to barotrauma mortality than red snapper. Although simila r percentages of red snapper (39%) and red grouper (40%) died from decompression injuries significant differences between species were apparent. Red snapper mortality was 40% for fish decompressed from 42.7 m and 45% for fish from 61.0 m. For red grouper 75% of the fish tested at 42.7 m died. Red grouper mortality at 42.7 m was so high duri ng the first trial that no 61.0 m simulation experiments were attempted (Table 3-1). In previous studies, re d grouper exhibited 50% mortality at 27.4 m while red snapper had 0% mortality in trials at this depth (Joakim Malmgren, personal communication). Acute mortality caused by barotraumas in red grouper accounted for 100% of all red groupe r mortality, while 71% of red snapper mortality was acute (Table 3-2). Table 3-1. Red snapper and red grouper mortalities during hyperbaric chamber tests. Data include number of mortalities for each depth, % of all fish test ed by species, % of all fish tested at depth by species, and % of all mortalities by depth. Depth (m) 21.3 27.4 42.7 61.0 % of species Red snapper # of mortalities 0 0 8 9 39.0 % by depth 0 0 40.0 45.0 % of all RS mortalities 0 0 47.1 53.0 Red grouper # of mortalities 0 2 6 40.0 % by depth 0 50.0 75.0 % of all RG mortalities 0 25.0 75.0

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84 Table 3-2. Acute and delayed mortaliti es of red snapper and red grouper from hyperbaric chamber tests. Acute Delayed Total mortalities % acute % delayed Red snapper 12 5 17 71.0 29.0 Red grouper 8 0 8 100.0 0.0 Signs of trauma and fish be havior during and following the hyperbaric chamber studies Both red grouper and red snapper that had been acclimated to a simulated depth of 42.7 m and rapidly decompressed exhibited some external signs of depth induced trauma including distended abdomens, in testine protrusion ou t of the anus and stomach prolapse (Figure 3-13) when removed from the chambers mirroring those seen in fish caught during normal fishing at this depth. In addition, red grouper exhibited bilateral pressu re-induced exophthalmia (Figure 3-14) that was unique to red grouper throughout the course of these experiments. Another difference between red grouper and red snapper was that most vented red snapper released into holding/recovery tanks immediately swam to the bottom and remained in the upright position on the bottom and behaved normally and behaved normally. Venting had enabled them to acclimate immediately to 1 atm of pressure despite the psi they had been acclimated to during the experiments in the chambers. However, red grouper, especially those acclimated to Figure 3-13. Red snapper exhibiting stomach prolapse caused by swim bladder gas expansion following swim bladder rupture.

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85 42.7 m repeatedly dove straight down, bounced off the tank bottom and slowly floated to the surface exhibiting increasing external signs of barotraumas such as exopthalmia and bloating over time until they died in approximately 30 minutes. There were also differences in internal trauma. Necropsy results showed red grouper suffered much more extensive internal trauma than did red snapper. Although all fish regardless of species, suffered ruptured swim bladders when rapidly decompressed from 42.7 m or deeper, red grouper exhibited profuse internal hemorrhaging, even in some red grouper decompressed from 27.4 m. Hemorrhaging included bilateral clots in the post-cranial area and thoracic cavity. In c ontrast, red snapper exhi bited some visceral displacement and torsion, especially in those rapidly decompressed from 61.0 m; however, much less hemorrhaging was detected. Esophageal Ring Both red grouper and red snapper exhibited stomach prol apse caused by rapid decompression. Force produced by swim bladder gas expansion propelled the stomach through the esophagus with such strength ; it created a ring-like bruise formed when doubling over of the esophagus caused capillaries in the esophagus to burst (Figure 3-15). This ring-like esophageal bruise was an important discovery because it provided a physiognomic feature indicative of recent swim bladder rupture and stomach prolapse Figure 3-14. Pressure induced exopthalmia in a red grouper.

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86 caused by depth-related trauma. The “esophageal ring” remained for several days post swim bladder rupture and viewing the bruise was a tool to gauge the magnitude of depth-related trauma since it only occurred in response to stomach eversion into the oral cavity. Simulated Depths and Controlled Stepwise Decompression All red grouper and re d snapper survived the slow controlled incremental step-wise decompression experiments within hyperbaric chambers from the simulated depth of 42.7 m, but there were differences in both the number of pressure increments required to acclimatize fish back to ambient surface atmospheric pressure and decompression times between the two species Red grouper needed five pressure increments (63, 50, 35, 20 Table 3-3. Results of incremental step-wise decompression experiments in fish hyperbaric chambers to determine the number of pressure increments (number of stop s) needed for red grouper and red snapper to acclimate to surface pressu re (1 atm) after acclimation to a simulated depth of 42.7 m (4.3 atm). Pressure Increments (psi) Time (hrs) Red Grouper (n=8) 60 50 35 20 5 76.5 Red Snapper (n=8) 63 40 25 15 104.0 and 5 psi) to acclimate to 1 atm of pressure, re d snapper only required four (63, 40, 25 and 15 psi) (Table 3-3). Despite requiring an additional stop, red grouper spent less cumulative time (76.5 hours) becoming acclimated to the various simulated ascent depths Figure 3-15. Esophageal ring bruise caused by stomach prolapse in red sna pp er decom p ressed from 61 m.

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87 than red snapper (104 hours). Fish handli ng time averaged 51 s ec (standard deviation 21.9 sec) for all trials and all chambers, although some fish became trapped within the chamber by the inward opening chamber doors, resulting in longer handling/struggle times. Total handling time ranged 9-103 sec. Another difference was red grouper depressurization occurred at increasing greater increments of pressure (20, 30, 43, and 75%) from the previous pressure whereas red snapper depressurization occurred in approxima tely equal increments of 39, 37, and 40% decreases from the previous pressure. Initial acclimation time to the simulated depth of 42.7 meters (63 psi) also differed Red grouper took 71 hours to acclimate to depth while red snapper acclimated faster (52 hours). Fi nally, although red snapper needed more time to reacclimatize after each d ecrease in pressure, they were capable of handling larger pressure changes per incr ement than red grouper. Swim Bladder Healing Despite differences in severity of internal tr auma, in all fish that survived, regardless of species and simulated depth, swim bladder ru ptures showed signs of healing within 24 hours with tissue on both sides of the rupture te nuously connected along its entire length. All fish swim bladders healed enough to be functional within 2-4 days after removal from the chambers. Even extensive ruptures in bot h species healed within this time period. The inner layer (submucosa) (Figure 3-16) healed first allowing the swim bladder to hold gas. Newly healed tissue was nearly tran sparent and became increasingly opaque over time as the other layers, the muscularis mucosa (middle smooth muscle layer) and tunica

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88 externa (outer layer of connective tissue) (F igure 3-17). At the end of one month, the only visible sign of rupture was a line of scar tissue that persisted over time providing a physiognomic indicator of previous ruptures in caught and rel eased fish (Figure 3-18). Figure 3-17. Red snapper swim bladder rupture scar 3 days after rupture in 62 m hyperbaric chamber rapid decompression experiment. Rupture is healed sufficiently to be functional. Figure 3-16. Red snapper swim bladder rupture site showing healing in a fish sacrificed 2 days after rapid decompression from the simulated depth of 62 m in hyperbaric chambers.

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89 Figure 3-18. New swim bladder rupture from depth simulation of 21.3 m (tip of forceps) and healed scar (tip of scissors) from rupture at 21.3 m during capture one month previously. New ruptures did not occur in areas previously ruptured. It may be that the thicker scar tissue is more resistant to new injury than areas without scar tissue. Stomach Prolapse and Feeding One of the most common external signs of sw im bladder rupture was stomach prolapse. As long as stomach muscles were not severe d by the force of released swim bladder gases following swim bladder rupture, stomach muscles of vented fish pulled the stomach back into place within one hour. Red snapper that survived decompression from 42.7 m fed aggressively within four hours after be ing removed from the chambers; red grouper within 12-24 hours. In contrast, red grouper rapidly decompressed from simulated depths of 27.4 m and 21.3 m, fed within two hours after removal from the chambers (Figures 3-19 and 3-20). No fish within the control groups used in the hyperbaric chamber step-wise acclimatization/deco mpression experiments exhibited stomach

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90 prolapse. All fish within bot h groups fed within 1-2 hours following removal from the chambers. Fish Tag and Release Most releases and recaptures occurred dur ing hook-and-line fishing aboard private recreational and recreational-for-hire vessels Recapture data from headboats were Figure 3-20. Overall view of red snapper 7 days after rapid decompression experiment in hyperbaric chamber 42 m depth simulation. Note good condition of tissues and organs and evidence (shrimp) of normal feeding. Figure 3-19. Red snapper stomach one hour after stomach prolapse. Stomach is back in place an d fish can feed normally.

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91 highly under reported. Recaptured fish aboard al l headboats fishing in the Gulf of Mexico were only reported if MML staff or student interns were aboa rd. Crew stated recaptures occurred during other trips but crews were too busy to report them. Red grouper (n=8,765) were tagged and re leased from private recreational and recreational-for-hire vessels between October 9, 1990 and August 31, 2007 at depths ranging 6-81.7 m. Overall 5.5% (n= 484) of these fishes were reported recaptured, mostly between 2.1-45.7 m however a few fish (n= 4) were recaptured at depths 45.753.3 m. Red snapper (n=8,303) were al so tagged off private recreati onal and recreational-for-hire vessels during the same time period. Most were recaptured at depths ranging 12.530.5 m, the depths where most fish were initially tagged. Overall 8.1% (n=623) fish were reported recaptured. Recaptures decreased with depth (30.8 -36.6 m); however, a few fish (n=5) were recaptured at depths ranging 39.6-42.6 m. Differences in Survival by Fish Le ngth for Hook-and-Li ne Caught Fishes Despite demonstrated differences in their ab ility to tolerate rapid decompression with respect to barotrauma, both spec ies exhibited the same trend in survival from depth with respect to fish length. Analyses of combined recapture data from pr ivate recreational and recreational-for-hire vessels by fish length show ed more larger fish of both species were recaptured. The proportion of recaptured sma ll (< 38.1 cm FL) to larger red grouper (> 381 mm FL) was compared using a log-likeli hood G test. Sizes were chosen based on changes in swim bladder stru cture at around 38 cm in red gr ouper. Results were highly

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92 significant (p=9.7 x 10-19). Although red snapper never develop the secondary structure seen in red grouper, for consistency, the same size was used in analyses. Similar results were found when comparing recaptured small re d snapper (< 38.1 cm FL) to larger red snapper (> 38.1 cm FL) (p=9.5 x 10-6 ) (Table 3-4). When red grouper and red snapper recapture data were divided by sector (private recreational and recreational-for-hire) for anal ysis at a depth of 21.3 m, (depth of 100% survival from the chamber simulated studies ) and size limit of 40.6 cm, results differed by sector. Analyses were conducted fish le ngths < and > 40.6 because it was the red snapper size limit. The same size was used fo r red grouper for consistency. In the private recreational sector percent reca ptures favored survival of sm all fish for both species. Survival favored larger fish in the recreational-for hire sector for both species (Table 3-5). Although in some studies this difference may be attr ibutable to reporting rate, in this study, all hea dboat recaptures in the Gulf of Mexico were made by MML staff and student interns who recorded all r ecaptures regardless of size and many private recreational vessel owners were in terested in the tagging program. Table 3-4. Results of G tests comparing survival by fish length of small to large red grouper and red snapper using all recreational recaptures regardless of depth. Test Group No. Tagged No. Recaptured % Recaptured G test result ( p value) 38.1cm vs. > 38.1 cm Red Grouper < 38.1 cm 3308 194 5.9 9.7 x 10-19 > 38.1 cm 1675 240 14.3 df =1 Red Snapper < 38.1 cm 3957 333 8.4 9.47 x 10-06 > 38.1 cm 1518 196 12.9 df =1

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93 Tag and Release of Red Grouper Aboar d Commercial Long-line Vessels Undersized (n=866) and legal (n=50) red gr ouper were tagged and released during longline fishing trips aboard various commercial long-line fishing vesse ls in 2004 and 2005. Fish were tagged and released at 248 differe nt sites in the eastern Gulf of Mexico. Capture depths ranged 37.8-99 m. No red snapper were captured during these fishing trips. Table 3-5. Red grouper and red snapper recaptures by fish length and fishing sector for fishes tagged and recaptured at 21.3 m. Depth was chosen because cham ber studies showed 100% survival for both species at this depth. Fish length was chos en because it was the legal size limit for Gulf of Mexico red snapper and for red grouper it provided both consistency and a larger sample size for analyses. Private Rec = private recreational vesse ls; Rec-for-Hire = recreational-for-hire vessels. Red Grouper Sector Size (cm) No. Tagged No. Recaptured % Recaptured G crit & p value Private Rec 40.6 1029 127 12.3 G =3.84 > 40.6 261 33 12.6 p =0.922 Rec-for-Hire 40.6 6419 283 4.4 G= 3.84 > 40.6 1083 116 10.7 p =4.02x10-13 Red Snapper Private Rec 40.6 270 34 12.6 G=3.84 > 40.6 27 3 11.1 p =0.845 Rec-for-Hire 40.6 1230 102 8.3 G=3.84 > 40.6 296 50 16.9 p =0.00021

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94 Figure 3-21. Red grouper immediately following hook extraction after being brought up during a long-line set. Note lack of external signs of rapid decompression. Of 916 released fish, 711 (78%) were observed to have immediately swum straight down post-release, 67 (7%) swam down slowly, and 175 (19%) floated at the surface. Red grouper caught at the same dept h during the same long-line set varied in degree of outer signs of barotraumas from none to severe (F igures 3-21 and 3-22). Table 3-6 provides a breakdown of the immediate post-release fate of these fish by species, season, and depth. Eight released red grouper did not fall into these categories. One was eaten by a dolphin upon release; the rest (n=7) were not observed postrelease; however, all suffered from trauma during capture. Three of the seven were covered with bite marks, one was gut hooked and two suffered some degree of Figure 3-22. Red grouper caught on the same long-line set exhibiting various degrees of exophthalmia.

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95 exophthalmia, although still alive. Thirteen (0.14%) of these fish were recaptured within approximately two years (64-715 days) of release. Growth ranged 25.4-241.3 mm depending on duration between original captu re and recapture, a rate of .127-.635 mm. Additional red grouper were tagged off co mmercial vessels using three different commercial gear types, rod and reel, electr ic rod and reel and long-line during normal fishing trips aboard commercial vessels at depths ranging 24.4-80.5 m. Recaptures (n=45) were at liberty between 3-2,172 days. Most (76%) recaptured fish were vented before release (Table 3-6). Winter (12/1 to 2/28) Spring (3/1 to 5/31) Depth (m) 037 38-53 5468 69-83 84-99 0-37 38-53 54-68 69-83 84-99 Species Red Grouper Straight Down 30 10 46 4 224 68 133 10 Down Slow 1 7 1 2 11 11 24 4 Floating 11 11 20 3 27 13 38 6 Other 0 1 0 0 0 2 1 0 Summer (6/1 to 8/31) Fall (9/1 to 11/30) Depth (m) 0-37 38-53 54-68 69-83 8499 0-37 38-53 54-68 69-83 84-99 Species Red Grouper Straight Down 50 0 86 46 2 Down Slow 0 1 1 3 0 Floating 1 3 9 30 1 Other 1 0 1 1 1 Table 3-6. Immediate release fate of red grouper caught, vented, tagged, and released off long-line vessels on observer trips by species, tag depth (m), and season.

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96 Fish Venting Red grouper (n= 5,391 vented; n=1,932 not ve nted) and red snapper (n=5,694 vented; n=2,144 not vented) from the Fish Tagging Prog ram that had data in all categories (tag depth, recapture depth, and treatment) were us ed to test survival of vented versus not vented red grouper and red snapper. For re d grouper (n=322 vented; n=192 not vented) and red snapper (n=441vented; n=90 not vent ed) tagged and released from private recreational and recreational-for-h ire vessels for fish of both species in the shallow water control group (fish caugh t on hook-and-line at 21 m) where barotrauma was not an issue, showed no significant difference in survival rates for vented and not vented red grouper (p=0.8671) or red snapper (p=0.8376) indicating venting in and of itself did not cause mortality (Table 3-7). Tables 3-8 and 3-9 show tag and recapture data for vented and not vented red grouper and red snapper by depth. Fish of both species showed significance at Table 3-7. Red Grouper and red snapper tagged a nd released in the shallow water control group (fish caught at 21 m) where barotrauma was not an issue that were vented or not vented before release. Species No. Tagged & Vented No. Recaps & Vented % Recap No. Tagged Not Vented No. Recaps Not Vented % Recap G crit p value Red Grouper 322 27 8.4 192 17 8.9 3.8414 0.8671 Red Snapper 441 36 8.2 90 8 8.9 3.8414 0.8376

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97 Table 3-8. Red grouper tagged and released by treat ment (vented or not vented) by depth. Depth (m) No. Tagged & Vented No. Recaps & Vented % Recap No. Tagged Not Vented No. Recaps Not Vented % Recap G crit p value 22, < 27 2,586 254 9.82 1,389 185 13.32 3.841 0.0031 27, < 43 1,423 117 8.22 448 42 9.38 3.841 0.4907 43,< 61 927 42 4.53 79 7 8.86 3.841 0.1490 61 455 6 1.32 16 1 6.25 3.841 0.3598 Total 5,391 419 1,932 235 Table 3-9. Red snapper tagged and released by treat ment (vented or not vented) by depth. vented red grouper and red snapper by depth. Fish of both species showed significance at depths 22 and < 27 m with more not vented fish recaptured; however, at deeper depths there was no significant differences in surv ival. Field data differed from chamber study results as vented fish exhibited less trauma than not vented fish at 21 and 23 m for both species and for red snapper at deeper depths. Depth (m) No. Tagged & Vented No. Recaps & Vented % Recap No. Tagged Not Vented No. Recaps Not Vented % Recap G crit p value 22, < 27 2,088 206 9.87 1,403 194 13.83 3.841 0.0015 27, < 43 3,459 181 5.23 711 51 7.17 3.841 0.0614 43,< 61 135 3 2.2 28 1 3.57 3.8414 0.7279 61 12 0 2 0 Total 5,694 390 2,144 246

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98 Table 3-10. Number of fish caught and percent survival rate by depth in commercial fish traps. Depth (m) Species Caught Survived % Survived 52-64 Vermilion 393692.3 Bank Sea Bass 11100 Red Grouper 151493.3 Porgy 11100 65-76 Vermilion 77100 Bank Sea Bass 100 Red Grouper 000 Porgy 000 77-82 Vermilion 1300 Bank Sea Bass 500 Red Grouper 7571.4 Porgy 000 83-91 Vermilion 44100 Bank Sea Bass 000 Red Grouper 11100 Porgy 000 > 92 Vermilion 000 Bank Sea Bass 000 Red Grouper 000 Porgy 000 Some (n=26) red grouper that were tagged and released off private recreational and recreational-for-hire vessels were recaptured 65-868 days later by commercial fishers. Tagging depth varied 3.7-80.5 m. Most (69%) recaptured fish had been vented before release. Red grouper recaptures (n=42) from tagging depths ranging 24.4-80.5 m, originally tagged in the commercial fishery by commercial long-line (n =27), electric reel (n=5) and rod and reel (n=12) showed 81% of recaptured fish had been vented before release.

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99 Fish Caught in Commercial Reef Fish Traps Only four fish species were caugh t in the traps including red grouper (E. morio), vermilion snapper (Rhomboplites aurorubens), bank sea bass (Centropristis ocyurus) and littlehead porgy (Calamus proridens). No red snapper were caught. The most abundant fish caught were vermilion snapper (Table 3-11). Regardless of capture depth, most commercial trap caught fishes did not display outward signs of barotrauma. The few red grouper that did exhibit stomach prolapse appeared to otherwise be healthy. Although few (93) fi sh were caught, immediate survival was high over all depths fished and 92% were deemed to be in good condition and swam straight down following release. Unlike fishes caught at depth by other gear types, many trap caught released fishes did not require ve nting before release including red grouper. Twenty-two red grouper (6 legal, 16 undersiz ed) caught in the traps were tagged and released, one fish was sacrificed. One red grouper was recaptured after 315 days of freedom. Originally caught by commercial trap at 62.2 m (Site 1) it did not require venting be fore release. At release it was 48.3 cm FL and was recaptured at a dept h of 34.7 m on rod and reel and reported to have grown to 58.4 cm. Although most red grouper were tagged and released, a few were sacrificed under the auspices of a federal scientific permit to determine swim bladder condition and internal organs for abnormalities or damage caused by rapid decompression. Trap caught red grouper brought to the surface from 63 m s howed no outward appearance of depth-

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100 induced trauma. Sacrificed red grouper showed that although some swim bladders ruptured, no internal hemorrhag ing occurred. Internal organs appeared normal in some fish; however, a few had pinhole sized damage to their deflated swim bladders and/or torqued internal organs. Trap Fish Survival by Ascent Treatments Ascent rate for hand over hand trap retrieval averaged 0.45 m/sec, while winch retrieved traps ascended at an average rate of 1.22 m/ sec. Although multiple experimental trials were originally scheduled for offshore tr ips off commercial fishing vessels during 2004 and 2005, only one set of experiments was possible during the time frame because offshore trips were continuously cancelled due to an inordinate number of hurricanes, tropical storms and weather front s. Data were very limited and are shown as Table 3-11.

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101 SOAK RELEASED SITELOCATIONDATETRAP#TIMEMFtTIMEDMETHODCATCHCONDITION (mm:ss.oo)(m/sec)(ft/sec) 126.58/83.425/16/200614 HR63.120700:26:34WINCH2.407.86RG & VS1 SAC, 3 FLT, 2SD 126.58/83.425/16/200624 HR63.120701:52:19BY HAND0.561.84RG & VS1 SAC, 1 SD 126.57/83.415/16/200634 HR62.220401:01:97WINCH1.003.30NO FISH 126.57/83.415/16/200644 HR62.220402:23:37BY HAND0.431.42RG12 SD 126.56/83.405/16/200654 HR61.020001:14:31WINCH0.822.69VS9 SD 126.56/83.405/16/200664 HR61.020001:44:47BY HAND0.581.91NO FISH 326.05/83.455/17/200674 HR89.929502:40:03BY HAND0.561.84NO FISH 326.05/83.455/17/200684 HR89.929501:04:75WINCH1.394.56RG1 SD 326.03/83.445/17/200694 HR88.729102:56:50BY HAND0.501.65NO FISH 326.03/83.445/17/2006104 HR88.7291 326.02/83.445/17/2006114 HR90.829802:28:97BY HAND0.612.00VS4 SD 326.02/83.445/17/2006124 HR90.829801:23:65WINCH1.093.56NO FISH 425.37/83.425/18/20061314 HR79.226001:32:44WINCH0.862.81RG5 SD, 2 FLT 425.56/83.425/18/20061414 HR79.226003:07:63BY HAND0.421.39NO FISH 425.56/83.425/18/20061514 HR81.726801:03:09WINCH1.294.25VS12 SD 425.55/83.425/18/20061614 HR79.926202:52:09BY HAND0.461.52CRAB & BSB3 SD 425.55/83.415/18/20061714 HR80.826502:30:97BY HAND0.541.76VS & BSB3 SD 525.54/83.345/18/2006184 HR71.323401:15:59WINCH0.943.10VS & BSB4 SD 525.54/83.345/18/2006194 HR71.623502:52:59BY HAND0.411.36VS4 SD 525.55/83.345/18/2006204 HR71.023300:59:78WINCH1.193.90NO FISH 525.56/83.355/18/2006214 HR72.223703:09:65BY HAND0.381.25NO FISH 525.56/83.355/18/2006224 HR71.923603:36:16BY HAND0.331.09NO FISH 626.12/83.135/19/2006234 HR51.817001:00:56WINCH0.862.81VS4 SD 626.12/83.135/19/2006244 HR51.817002:12:28BY HAND0.391.28VS & PORGY12 SD 626.11/83.125/19/2006254 HR51.817000:53:31WINCH0.973.19NO FISH 626.10/83.125/19/2006264 HR51.817002:17:28BY HAND0.381.24VS4 SD 626.10/83.125/19/2006274 HR52.417202:09:78BY HAND0.401.33NO FISH 226.25/83.555/20/2006284 HR115.838001:12:57WINCH1.605.23NO FISH 226.25/83.555/20/2006294 HR115.838004:10:31BY HAND0.461.52CRAB1 SD 226.26/83.555/20/2006304 HR115.838001:18:91WINCH1.474.82NO FISH 226.26/83.555/20/2006314 HR114.937704:17:84BY HAND0.250.82NO FISH 226.27/83.555/20/2006324 HR115.838004:39:06BY HAND0.411.36NO FISH SPECIES CONDITION RGRED GROUPERSACSACRIFICED VSVERMILION SNAPPERFLTFLOATED BSBBANK SEA BASSSDSTRAIGHT DOWN RATE RETRIEVAL LOST TRAP DEPTHRETRIEVAL Table 3-11. Ascent rate of fish retrieved by hand and winch.

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102 Red Grouper Purchased from Commercial Fish Trappers None of the ten red grouper purchased from commercial fish trappers showed outward signs of depth-induced trauma (Figure 3-23), despite capture depths of 55-61 m. Many had intact gas filled swim bladders (Figure 3-24) and lacked any discernable internal trauma (Figure 3-25); however, a few had pinhole sized damage to their deflated swim bladders and/or torqued internal organs (Figures 3-26 through 3-28). Figure 3 24. Intact inflated swim bladder excised from a 70.0 cm red grouper caught by commercial fish trap (55m). Figure 3-23. Commercial trap captu red red groupers caught at 55-61 m note xhibitingthecommonexternalsignsofbarotraumas.

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103 Figure 3-25 Intact normally positioned stomach from a 58.0 cm red grouper caught in a commercial fish trap (55-61m). Figure 3-26. Swim bladder of a 70.0 cm red grouper caught in a commercial fish trap. Note pre-pinhole formation and semi-transparent stretched tissue of posterior portion of the swim bladder.

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104 Figure 3-28. Swim bladder tear in a 57.7 cm commercial trap caught red grouper (55-61 m). Figure 3-27. Swim bladder from a 67.5 cm commercial trap caught red grouper exhibiting pinhole trauma (55-61 m).

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105 Discussion Acute Mortality Swim bladder rupture occurre d in all red grouper and re d snapper caught on hook-andline at depths ranging 10 m. Although the degree of a pparent bloating and other capture related symptoms increases with depth in phys oclistic fishes, swim bladder ruptures are not necessarily lethal (Collins et al. 1999, Wilson 1993, Wilson and Burns 1996). Results from hyperbaric chamber experiments agreed with tag recapture data showing red snapper suffered less severe trauma than red grouper with respect to rapid decompression at least at depths 42.7 m, especially if swim bl adder gases were released through venting or if the fish were rapidly recompresse d. Direct observati ons using hyperbaric chambers showed red snapper rapidly deco mpressed at depths of 62 m can survive at surface depths (1 atm) if swim bladder ga ses were released. Red grouper could not survive at 1 atm from this depth if simply vented in the laboratory where they were unable to return to acclimated depth. They required rapid recompre ssion to survive rapid decompression from this depth. Jarvis and Lo we (2008) also found degree of barotrauma injury and fish survival was species-specific for the various species of rockfishes tested and that rapid recompression of rockfish caught at 55-89 m enhanced survival. Swim Bladder Differences Differences in anatomy and physiology between red grouper and red snapper influenced survival Red grouper with their capac ious thinner swim bladde rs have the capacity to hold greater quantities of swim bladder gases than the smaller th icker red snapper swim bladders resulting in much larger swim bla dder tears during rapid decompression. Jarvis and Lowe (2008) also found disparities in swim bladder tissue thickness among various

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106 species of rockfishes and have postula ted that swim bladder morphology may be responsible for differences in swim bladder tear incidence They reported olive rockfish swim bladders with comparatively thin swim bladders had more severe swim bladder tears than other rockfish species with th icker swim bladder tissue and suffered higher mortality from barotraumas than other rockfish species such as vermilion, copper, and brown rockfishes that all have thicker swim bladders. Tissue thickness is not the only morphologi cal difference between red grouper and red snapper swim bladders. Brow n-Peterson and Overstreet (B urns et al. 2008) showed blood vessels are more closely associated with rete in red grouper than in red snapper which probably contributes to the increased hemorrhaging in blood vessels associated with the swim bladders of red grouper, rega rdless of fish length. They reported red grouper swim bladders had less rete than those of re d snapper possibly reducing gas exchange efficiency because fewer capillar ies were available fo r gas absorption and resorption. Additionally, the close associa tion and numerous conn ections between rete and other blood vessels with gas gland tissue in red grouper swim bl adders reported by Brown-Peterson et al. (2006) probably promotes hemorrh aging during swim bladder rupture increasing internal tr auma. These factors combined w ith a larger quantity of gas may be responsible for observed larger ruptur es in the thin membrane of the red grouper swim bladder. Reduced gas exchange resulting in increased internal pressure may have propelled escaped swim bladder gases to the eyes a nd crania resulting in the characteristic

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107 exophthalmia and cranial hemorrhaging commonl y seen in red grouper caught in waters deeper than 27 m. Red grouper exhibited various degr ees of exophthalmia, from all depths tested except 21.3 m. In all cases exophthalmia always occurred in both eyes simultaneously. Necropsies revealed the pr esence of gas behind bot h eyeballs when red grouper suffered from exophthalmia. The volume of gas present appeared to be too great to be accounted for simply by dissolved gas in tissues. It appeared swim bladder rupture also released gas into the ventral coelom and orbital regions, multiplying damage within the fish. This parallels results reported by Rogers et al. (2008) w ho reported an analogous response in rapidly decompre ssed rockfish, where escaped expanding gases following swim bladder rupture burst the peritoneum, entered the orbital regions, and increased pressure behind the eyes resulting in exophthalmia In contrast, the smaller red snapper swim bl adder contains more retal area in the swim bladder than red grouper by fish length (p<0.001), which Brow n-Peterson and Overstreet (Burns et al. 2008) postulated should increase gas exchange rates. Higher exchange efficiency of a smaller volume of gases combined with thicker tissue probably resulted in the smaller swim bladder tears observed in red snapper. Addi tionally, unlike the red grouper swim bladder, most rete in red snapper swim bladders were segregated from gas gland cells probably reduci ng the amount of hemorrhagi ng. This separation was especially apparent in smaller red sna pper swim bladders (Brown-Peterson and Overstreet in Burns et al. 2008).

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108 The intimate association of larger blood vesse ls, rete and gas gland tissue in red grouper probably leads to increased retal hemorrhaging with rapid decompressi on in all lengths of red grouper. Brown-Peterson and Overstreet (Bur ns et al. 2008) stated that “histological results show overall that red snapper su rvive rapid decompression better than red grouper, as evidenced by reduced mortality, sm aller and less frequent tears in the swim bladder, and less of a tendency to hemorrhage, particularly in smaller fish. The higher percentage of rete area in the swim bladder of red sna pper compared with red grouper suggests swim bladder gasses may be exchange d more rapidly in red snapper, allowing greater survival after rapi d decompression.” Although vari ous authors have postulated that differences in intrasp ecific trauma of fishes caught at similar depths may be explained by relative swim bladder volum e at capture (Arnold and Walker 1992, Rummer and Bennett 2005, Parker et al 2006), for red grouper and red snapper differences in swim bladder structure doc umented by Brown-Peterson and Overstreet (Burns et al. 2008) are also important in determ ining the variations in trauma and survival from different depths for the two species. Laboratory Simulations of Depth Eff ects Using Fish Hyperbaric Chambers Although red grouper and red sn apper swim bladder ruptur es occurred at depths 10m, neither species suffered mortality duri ng rapid decompression from depths 21.3 m. Tag and recapture data agreed showing higher recapture (survival) rates from shallow depths. Koenig (2001) reported rapid decompression from 20.0 m was not onl y non-lethal to red grouper and red snapper, but fishes caught, held and retrieved from cages at this depth for 13 days, were in excellent condition.

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109 Differences between red grouper and red snappe r survival occurred at simulated depths > 21.3 m. Overall, red grouper were much more susceptible to depth-related trauma than red snapper. Although 100% of the red groupe r survived the 21.3 m experiments, only 50% of red grouper survived th e 27.4 m depth simulations e xperiments and less (25%) of the red grouper survived duri ng the 42.7 m chamber experime nts. The 25% red grouper survival rate in the chambers was far less th an the 85% survival rate reported by Wilson and Burns (1996) for potential survival from shipboard experimentation experiments. Red grouper were vented after removal from the hyperbaric chambers and placed into holding tanks at 1 atm to observe recovery. They were unable to return immediately to acclimated depth as were the fish returned in cages at sea. Data from the depth simulation studies conducted in hyperbaric chambers showed although some red snapper suffered mortalit y or sub-lethal e ffects during rapid decompression from depths 42 m, others survived at 1 at m of pressure if vented. In contrast, red grouper never survived rapid decompression from these depths to 1 atm pressure in the laboratory, even when vented they must rapidly recompress at acclimation depth (Burns et al. 2004). Although rapid recompression co uld not be accomplished in laboratory holding tanks, when achieved thr ough slow controlled in cremental step-wise decompression experiments with in hyperbaric chambers fr om the simulated depth of 42.7 m, all red grouper and red snapper survived, albeit there were diffe rences in both the number of pressure increments required to acclimatize fish back to ambient surface atmospheric pressure and decompression tim es between the two species. Red grouper required five pressure increments (63, 50, 35, 20 and 5 psi) to acclimate to 1 atm of

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110 pressure, red snapper only needed four (63, 40, 25 and 15 psi). Despite requiring an additional stop, red grouper spent less cu mulative time (76.5 hours) becoming acclimated to the various simulated ascent depths than red snapper (104 hours). In addition, red grouper depressurization occurred at increasing greater increments of pressure (20, 30, 43 and 75%) from the previous pressure whereas red snapper depressurization occurred in approximately equal increments of 39, 37 and 40% decreases from the previous pressure. Initial acclimation time to the simulated depth of 42.7 meters (63 psi) also differed Red grouper took 71 hours to acclimate to depth while red snapper acclimated faster (52 hours). Finally, although red snapper needed more time to reacclimatize after each decrease in pressure, they were capable of handling larger pressure changes per increment than red grouper. At sea, Wilson (1993) reported a 95% survival rate for red grouper caught on hook-and-line and returned an d held in cages at 43 m for up to eight days following the return of these fishes to in situ conditions. Data were consistent with laboratory results from MA RFIN Award NA97FF0349 of red grouper and red snapper subjected to depth simulations in fish hyperbaric chambers (Burns et al. 2004). Swim bla dders of both species ruptured with a change from 1 to 2 atm of pressure (10-20 m); however, both species easily survived capture from these depths as well as rapid decompression from 21 m (100% survival). There are, however, marked differences in their ability to tole rate rapid decompression from deeper depths (> 27 m). Data from depth simulations of 27.4 m in hyperbaric chambers have shown variable survival due to he morrhaging in some red grouper, but results for red snapper show 100% survival with no complication. While some red snapper did suffer mortality

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111 or sub-lethal effects during rapid decompression from simulated depths 42 m, many survived when held at 1 atm pressure if vented. In contrast, red grouper never survived rapid decompression from simulated depths of 42 m to 1 atm pressure, even when vented (Burns et al. 2004). However, fiel d data have shown that red grouper can survive rapid decompression from depths of 61 m or greater, if the fish were vented and immediately allowed to return to the prio r habitat depth (Wilson and Burns 1996, Burns and Robbins 2006), criteria which coul d not be met in laboratory studies. Hyperbaric Chambers Red grouper in this study were vented afte r removal from the hyperbaric chambers and placed into holding tanks at 1 atm to observe recovery. They were unable to return immediately to acclimated depth. During necropsies the physical effects of rapid decompression on red grouper were obvious and showed they suffere d more internal trauma than red snapper at the same depths. This was evident in the presence of massive visceral hemorrhaging and bilate ral cranial clots unique to red grouper. Red grouper also exhibited various degrees of exophthalmia, from all depths tested except 21.3 m. In all cases exophthalmia always occurred in both ey es simultaneously and to the same extent. Necropsies revealed that gas was actually present behind the eyeb all when red grouper suffered from exophthalmia. The volume of ga s present appeared to be too great to be accounted for simply by dissolved gas in tissues It appears that when the swim bladder bursts more gas is released into the ventral coelom, increasing the amount of damage to the fish. This parallels results reported for some species of rockfish (Rogers et al. 2008).

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112 Venting these fishes was not successful in removing all swim bladder gases to prevent internal trauma caused by emboli formation w ithin blood vessels and organs, especially the cranium and blood vessels leading to the ey es. The condition of the red grouper immediately removed from the chambers appeared viable. Fish were energetic and lively when first placed into the recovery tanks, repeatedly swimming down to the bottom of the tank trying to return to acclimatized dept h. Rapidly fish began to exhibit more obvious and extreme external physical signs of depth induced trauma until death occurred within hour after re moval from the chamber. Rogers et al. (2008) reported a greater than 75% initial capture for ro ckfishes within the first 10 minutes of capture in spite of “species-specific differences in the types and degree of angling-induced barotrauma.” In the Wilson and Burns (1996) study, re d grouper caught at 42 m and 43 m were immediately placed into the shipboard hyperb aric chambers for repressurization to determine survival rates when effects of rapid decompression were quickly countered. Survivorship was determined by the released fish’s “ability to sw im down rapidly and vigorously after release.” This is the reason for the disparity in survival between the two studies. Unlike the red grouper in the laboratory experiments th at were forced to remain at 1 atm of pressure, these fish were free to return to acclimatized pressure. On the other hand, results from the Wilson and Burns (1996) study are comparable to results from the controlled step-wise decompressi on portion of this study. Surv ival rate was 100% in this study versus the 85% reported by Wilson and Burns (1996); however, this disparity is probably due to initial fish condi tion. Fish in the controlled step-wise decompression experiments were in excellent condition. Fish in the Wilson and Burns (1996) study

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113 suffered the ill effects of rapid decompression and some had hook damage and more than likely represent an accurate estimate of red grouper survival under real world conditions. In contrast to red grouper, red snapper did no t suffer as massive inte rnal trauma at the same simulated depths. The massive viscer al hemorrhaging and b ilateral cranial clots common in red grouper were never found in red sn apper, even in thos e used in the 61.0 m chamber experiments. The survival rate for red snapper at 42.7 m was 60% and is comparable to the 56% red snapper survival at depths of 37-40 m reported by Gitschlag and Renaud (1994) and the 50% survival rate at 36 m reported by Koenig (2001). The 55% red snapper survival rate at 61.0 m found during this stu dy supports previous findings of 60% survival at 50 m repor ted by Gitschlag and Renaud (1994). Red snapper are much less prone to exophthalmia at shallower depths due to anatomical differences and a smaller volume of swim bladder gases within their bodies following swim bladder rupture. A few red snapper e xhibited exophthalmia in one eye, a few in both eyes. In both scenarios the fish surv ived because the brain was undamaged. The fishes with exophthalmia in one eye were onl y blind in that eye and were capable of behaving normally and remained part of the school in the holding ta nks. Fish which had succumbed to exophthalmia in both eyes, while completely blind, were able to use their sense of smell to locate food and fed and thei r lateral line sense to remain upright within the tanks. Although they mostly remained on the bottom of the tanks, they survived for months within the tanks until they had to be humanely euthanized at the end of the study

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114 as they could not be released or put in disp lay tanks where they would starve because of competition by sighted individuals for food. No effect of handling time were detected nor was handling time in corporated into the study to influence survival for either species; however, the average handling time (51.2 sec) during year two may have been too low to realize any effects. Koenig (2001) found surface interval (analogous to handling time) to be strongly related to mortality. Surface intervals in his study ranged from 318 min, far longer than the 9-103 sec range during year two. However, during year one, longer handling ti me (3-10 min) was probably responsible for the more variable survival observed at 42.7 m and 61.0 m and this does agree with Koenig’s results. Ho lding time was also significant factor in rockfish survival (J arvis and Lowe 2008). Swim Bladder Healing Parker et al. (2006) sugges ted that longer-term surviv al may be compromised by structural damage to the swim bladder and (or) other organs. Despite differences in severity of internal trauma from the hyperbaric chamber expe riments, in all red grouper and red snapper that survived, regardless of simulated depth, sw im bladder ruptures showed signs of heali ng within 24 hours. Within 24 hours, the tissue on both sides of the rupture was tenuously connected along the entire length of th e rupture. All fish swim bladders were healed sufficien tly so as to be functional w ithin 2-4 days after chamber removal. The only visible sign of the rupture wa s a line of scar tissue. This line of scar tissue persisted over time and was used both in the laboratory and in the field as a physiognomic indicator of previ ous ruptures in captured a nd released fishes. Swim

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115 bladder rupture scars were also evident in fishes of both species that were caught on hook-and-line gear at depths > 10 m, not just experimental chamber fishes. These scars provide evidence that not only had the fishes been previous ly caught at depths > 10 m, but that they survived swim bladder rupture, healed and were then capable of resuming normal behavior. These data conflict w ith results reported by Rummer (2007) and Rummer and Bennett (2005) who stated that red snapper sw im bladder tear s required an average of 14 days for repair. Fish conditi on may have played a role in healing time. Live red snapper treatment upon arrival at each f acility as well as differences in seawater treatment and sanitation during holding and experimentation differed. Rummer and Bennett (2005) prophylactically treated their red snapper wi th 50.00 mg/L nitrofurazone, dipped fish in 0.30 mg/L CuSo4 for 60 minutes and quarantined them for five days in mg/L Dylox and 2.50 mg/L Mare x to eradicate bacterial, Amylodinium sp. and trematode infestation and then held fishes a minimum of 14 days in biologically filtered tanks before experimentation. A lthough fish in both studies had similar diets and were fed until sated, Rummer and Bennett (2005) did not feed fish for 24 hours before or during experimental trials. As seen in the methods section for this study, fish were only treated with a 5-minute freshwater dip with Formalin solution (2 drops 37% Formalin/3.8 liters of water) upon arrival but also dipped 7, 14, 21 and 28 days after the fi rst dip treatment to kill any ectoparasites that hatched after the first dip based on the life cycles of the ectoparasites encountered in the sieved bath wa ter. Fish were quara ntined for one month to identify any health or parasite problems, to eliminate the possibility of complications from latent hook mortality, and to acclimate fi sh to handling and laboratory surroundings. Following quarantine, fish were divided into different experiment al groups and well fed

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116 before being placed in the hyperbaric chambers Another difference may be in the water quality used in the two studies. Raw seaw ater filtration was c onducted through various types of filters was necessary to keep fish healthy. Possible explanations for this disparity may be the result of different methodology both in chamber construction and experimental treatm ent. Data collected for this study were obtained from fish necropsy where trauma a nd healing could be directly observed and photographed. Although Rumm er (2007) and Rummer and Bennett (2005) also necropsied their fish, they util ized two-dimensional X-ray images to determine simulated depth acclimation, decompression, swim bla dder rupture after ra pid decompression and organ displacement caused by expanding sw im bladder gases following rupture and determining tissue boundaries and gas occupied areas may have been difficult. They also measured organ dimensions to estimate volum es; a method subject to error (Rogers et al. 2008). Stomach Prolapse and Feeding Although red grouper took more time to recover and begin normal feeding than red snapper following rapid decompressed from 42.7 m in both species the fish’s stomach muscles pulled the stomach back into place and making normal feeding possible. Red grouper rapidly decompressed from 21.3 m a nd 27.4 m fed within two hours of removal from the chambers. Both species used in the step wise controlle d acclimation study fed within 1-2 hours of removal from the cham bers. To compare laboratory experimental fishes with those caught on hook-and-line, necropsies of red grouper and red snapper caught off headboats from depths > 10 m were conducted. These fishes showed evidence

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117 of recent stomach prolapse through the presen ce of the “esophageal ring.” Externally, these fish appeared healthy and well fed. The presence of food in their stomachs indicated that they were feeding normally and supports findings reported for chamber experiment fishes. In shallow waters, some fishers participating in the tag and release portion of this study reported multiple recaptures of undersized red grouper or red snapper that they had just tagged and released back into the water Same day red grouper recaptures were much more common and were reported to occur anyw here from immediately to 30 minutes to one hour after the original cap ture and release. These “hook happy” fish were reported to be lively and did not appear to suffer from the catch and release experience. Fish Tag and Release Recaptures from the tagging portion of this st udy also support red grouper survival after rapid recompression at sea. Data show ed vented red groupe r can survive rapid decompression from depths of 61 m or greater, if fish are vented and can immediately return to habitat depth (Wilson and Burn s 1996, Burns and Restrepo 2002, Burns and Robbins 2006), criteria that c ould not be accomplished in laboratory holding tanks that were only a few feet deep. The reason for the disparity in red grouper survival rates following release from the hyperbaric chambers and experiments at sea is that at sea red grouper could swim back to habitat depth. Fish are aware of the pre ssure at the depth to which they are acclimated and perceive pre ssure changes through se nsory nerve endings in the swim bladder wall that stretch or slacken in response to changes in pressure. These nerve endings that signal the fish’s brain to fi re swim bladder neurons to initiate deflation

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118 or inflation of the swim bl adder (Blaxter and Tyler 1972 Marshall 1970) must still function in fish with ruptured swim bla dders. Thus, fish quickly removed from acclimation depth and then released strive to return to acclimation depth. Returning to acclimation depth was possible fo r vented red grouper at sea, but although vented red grouper, removed from the chambe rs and placed into 900-liter holding tanks, attempted to swim back down to the depth at which they were acclimated within the chamber they could never achieve this depth. These fish kept swimming to the bottom of the tanks for half an hour, exhibiting more and more pr onounced external signs of barotrauma infiltrating the cranial area as time passed until they died. However, some of these fishes would have been expected to survive if they could rapidly recompress as observed for red grouper released at sea, return ed to depth in cages and the 100% survival during the controlled step-wise decompression. Fish mortality due to barotrauma is not equi valent to nitrogen narc osis that causes “the bends” in divers. Trauma in fish is the result of damage caused by emboli within the fish’s blood and organs. The gr eater amount of retal area shar ed by gas gland cells in the red grouper swim bladder as well as the quantit y of swim bladder ga ses within the more capacious red grouper swim bladder are pr obably responsible for the increased hemorrhaging that occurs in red grouper blood ve ssels associated with the swim bladder. The observed smaller extent of hemorrhaging that occurs in red snapper swim bladders probably results from the less intimate connectio n between rete and gas gland cells within

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119 the swim bladder and the lesse r quantity of swim bladder ga ses housed within the smaller swim bladder. Differences in Survival by Size Survivorship by fish size appears to vary by species. Bartholomew and Bohnsack (2005) summarized findings on mortality with respect to fish length and mortality from thirteen studies with varying results. Two stud ies (Taylor and White 1992, Malchoff and MacNeill 1995) found lower mortality for sm aller individuals for non-anadromous trout and striped bass. Studies on lake trout (Loftus 1986) and Chinook salmon (Bendock and Alexandersdottir 1993) reported higher mortality for larger fishes. Results from ten other studies on various species including cutthroat trout (Pauley and Thomas 1993), spotted seatrout (Murphy et al. 1995), ra inbow trout (Schisler and Be rgensen 1996), (striped bass (Bettoli and Osborne 1998, Nelson 1998), blue cod (Carbines 1999), black seabass and vermilion snapper (Collins et al. 1999) and common snook (T aylor et al. 2001) showed no difference in mortality rates by size. Fish length was also not a factor in red snapper survival according to Gitchlag and Renaud ( 1994); a finding at odds with results from this study. Although small red grouper (< 38.1cm) appear to lack a secondary area located at the posterior ventral swim bladder when vi ewed under a dissecti ng microscope, BrownPeterson and Overstreet (Burns et al. 2008) re port that histological examination of this area revealed that even small red grouper ( 25.1 cm) have some vascularized tissue, as represented by blood vessels and capillaries but no organized gas resorption/secretion area at this length as smaller fish may not require as much gas for buoyancy. This

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120 difference may play a part in the disparit y in fish survival by size and differences between species. Being a deeper bodied more robust fish than red snapper, it is not surprising it has a higher percentage of gas gland in the re te compared with red snapper at similar lengths. A benthic species, that remains in inshore nursery grounds until moving offshore with increased size, it probably requires additional assistance with gas exchange as it grows and begins it s offshore migration. Many fishers claim smaller fish of both spec ies survived rapid decompression from depth better than larger fish (personal communicatio n). Histological data by Brown-Peterson and Overstreet (Burns et al 2008) appear to support this claim. They reported that although retal hemorrhaging was significantly higher in red grouper than in red snapper when adjusted for length, the percentage of both red grouper and red snapper with hemorrhaging in both rete and the swim bla dder increased significantly by 50 mm fish length increments. Additionally, they repor ted hemorrhaging was rare in small red snapper compared with large red snapper; however, some hemorrhag ing occurred in all red grouper regardless of fish length. Koenig (2002) also found a positive trend for survival of smaller red grouper and red snapper over their larger counterparts during hi s analysis of the re lationship between size and mortality for both species caught at 35 m and 40 m and maintained in his in situ cage experiments. These findings also agree with those of W ilson (1993) who reported that none of the large (> 737 mm) red grouper or scamp in his in situ cage experiments at 73 m survived. Only the smaller (< 584 mm) fi sh caught at every station survived. He

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121 found size at recapture to be important, with only fish < 584 mm surviving in his in situ cages at depths of 43-73 m for up to th e eight-day project observation period. A log-likelihood G test was ru n for private recreational and recreational-for-hire recaptures by size from this study. Results showed a significant di fference in recapture rates for small ( 38.1 cm) and larger (> 38.1 cm) fish of both species (red grouper p=9.7x10-19; red snapper p=9.47x10-6). Results benefited surviv al of larger fish of both species. These results did not agree with those of swim bl adder histology and field study results reported by Koenig (2001) and Wilson (1993) and Brown-Peterson and Overstreet (Burns et al 2008). Released undersized red snappe r caught off charter vessels and headboats in the waters off the Florida Panhandle face heavy predation from bottlenose dolphins (Tursiops truncates) (personal communication h eadboat and charter boat captains) (Figure 3-29). Figure 3-29. Bottlenosed dolphin about to feed on an undersized red sna pp er j ust discarde d from a hea d b oat fishin g off Panama Cit y, Florida.

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122 During two trips in April 2003, confirmed and probable takes by dol phins constituted a total of 28% and 23% of the day’s catch. So me fish were removed directly from the hooks by dolphins before being landed (Burns et al. 2004). Similar predation has been reported for red grouper by recr eational-for-hire cap tains (personal communication) who reported dolphins know their schedules and fish ing locations and would meet vessels to prey on discarded fish. Since predation would favor surv ival of larger fish, privat e recreational a nd recreationalfor-hire data were analyzed separately. Priv ate recreational recapture data at 21.3 m (no barotrauma effects) showed no difference in recapture rates for small and large fish of both species, but recreational-for-hire data showed survival favored larger fish. Recaptures Aboard Commercial Long-line Vessels Although only 13 of the 916 red grouper originally caught, tagged and released on longline gear during this study we re recaptured, it showed that red grouper can survive this fishing process and rapid decompression from depths ranging 38.4-80.5 m. Most fish (85%) were originally caught in less than 70 m. Wilson (1993) dete rmined the potential survival of grouper to be no greater than 25% for fish caught at depths of 73 m. Conversely, he reported a potential surviv al of 95% at 43 m for red grouper under in situ conditions when protected in cages. Seasonal mortality of fish caught at depth, based on thermal shock caused by large differences in water and air temperature duri ng the summer has been reported for fish caught off charter and headboats off Texas (Sandra Diamond, pe rsonal communication)

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123 and off the Florida east coast (Roger DeBrul er, personal communication). This summer phenomena was not readily apparent in the sma ll sample of long-line caught reef fish off Southwest Florida as part of this study. More floaters were recorded during spring and fall. Most floaters suffered trauma resulti ng from depth-related injury as indicated by various degrees of exophthalmia, predation (som e bite marks to covered with bite marks), or gear related wounds (gut hooked). Predation at some comm ercially fished sites was high and occurred both during as cent through the water column during capture as well as upon release. Fish Venting Data from laboratory hyperbaric chamber e xperiments from this study show venting can provide an edge for survival of some species when fish are not allowed to return to habitat depth. Collins et al. (1999) reported enhanced survival of vented black sea bass (Centropristis striata). Benthic species can return to habitat depth and su rvive the two to four day healing process. However, Collins et al. (1999) found that venting vermilion snapper (Rhomboplites aurorubens) did not provide as great a benefit for this small water column species. However, a pelagic speci es with a ruptured swim bladder cannot maintain itself in the water co lumn for very long (Marshall 1973). A small vented water column species would be unable to mainta in its position and hover for two days to accommodate swim bladder healing, instea d it would sink to the bottom and become subject to bottom predators. In addition to the physiologica l trauma that physoclistic fish species experience during rapid ascent from depth, it a ppears that other f actors are involved that may modify the

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124 extent of damage experienced from rapid ch anges in pressure. Koenig (2001) who did not vent the fishes in his experiments found a significant “d irect and strong relationship between depth-related mortality and surface inte rval.” The longer a fish remains at the surface filled with expanding sw im bladder gasses within its body, the more internal trauma these gases will inflict. Venting re moves escaped swim bladder gases from the fish’s body cavity following sw im bladder rupture and reduced trauma in laboratory hyperbaric chamber studies. It can allow fish to regain control over buoyancy and return to habitat depth rather than floating at the surface where th e fish is subject to the elements and predation from seabirds, marine mamma ls, sharks and other predatory fishes. Venting, however, has no effect on existing emboli. Returning to habitat depth enables fish recompression if fish can retu rn rapidly to acclimation depth. Venting in and of itself did not cause red gr ouper or red snapper mortality but it also did not provide long-term effects. Results from Restrepo’s two models developed to analyze short-term (within one month of tagging = Mode l 1) and long-term (1 year or longer = Model 2) red grouper recaptures were devel oped early in the study (Burns and Restrepo 2002). Model 1 supported the hypothesis that fi sh venting improved immediate survival for fish caught at depths great er than 21.3 m. Model 2 sugge sted that, long-term survival was influenced more by other factors such as year, depth of captur e or location rather than venting, however; additional data collected showed that there appears to be little or no difference in fish survival in vented and not vented fish in th e field and immediately returned to capture depth but there may an advantage when fish are caught at depth and held at the surface such as for laboratory stud ies, as brood stock, aquarium displays, live

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125 fishing tournaments, etc. The short term Restrepo Model should be run with the new additional data. Fish Survival by Treatment Ascent rate for hand over hand trap retrieval av eraged 0.45 m/s (1.6 ft/sec), while winch retrieved traps ascended at an average rate of 1.22 m/s (4 ft/sec). Trial sample size was too small to perform statistical analyses. Although Gitschlag and Renaud (1994) implied ascent rates play an important role in dept h-induced mortality of red snapper, Koenig (2001) found no relationship betwee n ascent rate and mortality in determining survival of reef fishes including red groupe r and red snapper caught on elect ric reel from depths (1855 m) and held in traps over time. Fish Traps Wilson and Burns (1996) found for fishes captured on rod and reel, depth-induced mortality of undersized reef fish increased w ith depth. Results from fish hyperbaric chambers studies support this finding. Ho wever, many fish caught in commercial fish traps were lively and did not exhibit external severe depth-induced trauma with rapid depressurization and did not require venting prior to releas e. Review of videotaped trap ascent showed these fish did not struggle duri ng ascent. Those that struggled within the traps during ascent exhibited si gns of barotrauma. Although few fish were caught during the study, survival was high over all depths fished based on observer determination of fish condition. Of 93 fish cau ght, six were rated to be in poor condition, two in fair condition, and the rest (92%) in good conditi on. With the excepti on of one red grouper (rated as good), which was sacrificed for inte rnal examination, all fish in good and fair

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126 condition swam straight down after release. Only the six fish listed to be in poor condition floated. The low mortality seen in trap caught reef fishes, agrees with anecdotal information reported in a commercial trap sect or study conducted in 1995 that showed high survivorship of trap caught fish (Alverson 1998). Researchers at the NOAA/NMFS Panama City and Pa scagoula Laboratories have also noted differences in red grouper barotrauma captured in traps (Doug DeVries, persona l communication) and observed high survivorship of trap caught fi sh at deep depths during NOAA fish surveys in the Gulf of Mexico (Kevin Ra demacher, personal communication). Grouper from Commercial Fish Traps None of the purchased fish showed outward signs of depth-induced trauma, despite being captured at depths of 55-62 m. Many of the fish had intact gas filled swim bladders and lacked any discernable internal trauma; howev er, there were a few others that suffered from pinhole sized trauma to the swim bladde r and were heavily tor qued internally and it is unknown if these effects prove lethal ove r time. In their cage holding experiments, Rogers et al. (2008) found that in general, more (50%) fish with organ torsion died as opposed to those (28%) with no organ torsion; however, th ey found this difference was not significant. Results suggest differences in depth-induced mortality in red groupe r and red snapper are related to swim bladder morphology and fi sh anatomy and physiology. Swim bladder characteristics appear to be speciesspecific rather than family-specific and appear to contribute to the variation re ported in survival from rapi d decompression. Jarvis and Lowe (2008) concluded that th e observable outward signs of barotrauma on the various

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127 rockfish species in their study “appear to be related to species differences in body morphology and also to the degree of vertical movement within the water column.” They reported that deep bodied more demersal rock fish species exhibited greater barotrauma than “elongate, laterally compressed bodied” mo re pelagic species. Results from this study support their findings. Red grouper, a ro bust, truly benthic sp ecies, has a capacious thin membraned swim bladder necessarily capable of holding a la rge volume of swim bladder gases that is subject to large ruptures and can cause fatal injuries during rapid decompression. The intimate association to re te, larger blood vessels and gas gland in the red grouper swim bladder resu lts in increased hemorrhagi ng. Red snapper, a more streamlined pelagic schooling species, have smaller thicker swim bladders capable of holding less swim bladder gas and is prone to smaller tears. More rete in the red snapper swim bladder make gas exchange more effi cient resulting in less hemorrhaging at all sizes(Brown-Peterson and Overst reet in Burns 2008). Howeve r, histological data, cage studies and data from private recreational tag recaptures supp ort the minimum size rule as smaller red grouper and red snapper survive ra pid decompression better than larger fish. Ecomorphology and a fish’s physiology and behavi or appear to be important factors in predicting survival during rapid decompressi on. Many pelagic spec ies feed on elusive prey such as other fishes and squid while truly demersal species tend to be benthic ambush predators or feed on invertebrates. Pe lagic species, more lik ely to travel through various depths on a regular basis than truly benthic species, may have evolved thicker swim bladders to more easily deal with pressure changes. Additionally, pelagic species are more streamlined than demersal species and may require less swim bladder gas for

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128 buoyancy. Another factor may be due to phys iological changes rela ted to the amount of physical activity (how much the fish struggl es) during ascent from depth that occur during fishing activities (Lee and Be rgersen 1996, Wilde et al. 2000). References Cited Alverson, D.L. 1998. Discarding practices a nd unobserved fishing mortality in marine fisheries: an update. Washington Sea Gran t Program, Seattle, Washington. 76 p Bartholomew, A. and J.A. Bohnsack. 2005. A review of catch-and-release angling mortality with implications for no-take reserves. Reviews in Fish Biology and Fisheries 15:129-154 Bendock, T. and M. Alexandersdottir. 1993. Hooking mortality of Chinook salmon released in the Kenai River, Alaska. North American Journal of Fisheries Management 13:540-549 Bettoli, P.W. and R.S. Osborne. 1998. Hooking mortality and behavior of striped bass following catch and release angling. North American Journal of Fisheries Management 18: 609-615 Blaxter J.H.S. and P. Tytler. 1972. Pressure discrimination in teleost fish. p. 417443. In: The Effects of Pressure on Organisms. Symposia of the Society for Experimental Biology (ed.) Cambridge: At the University Press, London NW 1 2 DB Brown-Peterson, N.J., K.M. Burns and R. M. Overstreet. 2006. Swim bladder morphology differences in red snapper and red grouper. Abstracts of the Joint Meeting of Ichthyologists and Herpetologist s, New Orleans, Loui siana, July 6-11, 2006. p. 61 Burns, K. 2001a. Venting of some bottom fish aids survival. Salt Water Sportsman Annual Pro Issue. May 2001. Burns, K.M. 2001b. Fish venting. Mote Marine Laboratory. Available: http://isurus.mote.org/resear ch/cfe/fish-bio-how-to-vent-a -fish.html. (January 2006). Burns, K.M., C.C. Koenig, and F.C. Coleman. 2002. Evaluation of multiple factors involved in release mortality of undersi zed red grouper, gag, red snapper, and vermilion snapper. Mote Marine Labora tory Technical Report No. 814. (MARFIN grant # NA87FF0421).

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129 Burns, K.M. and V. Restrepo. 2002. Survival of Reef Fish after Ra pid Depressurization: Field and Laboratory Studies. p. 148-151. In: Lucy, J.A. and A.L. Studholme (eds.) Catch and Release in Marine Recreational Fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland. Burns, K., N. Parnell and R. Wilson. 2004. Partitioning release mortality in the undersized red snapper bycatch: compar ison of depth versus hooking effects. MARFIN final report No. NA97FF0349, Mote Marine Laboratory Technical Report 932. 36 p. Burns, K.M. and B.D. Robbins. 2006. Cooperative long-line sampling of the west Florida shelf shallow water grouper comple x: Characterization of life history, undersized bycatch and targeted habitat. Mote Marine Laborato ry Technical report No. 1119. 46 p. Burns, K.M., N.J. Brown-Peterson, R.M. Overst reet, J. Gannon, P. Simmons, J. Sprinkle and C. Weaver. 2008. Evaluation of th e Efficacy of the Current Minimum Size Regulation for Selected Reef Fish Based on Release Mortality and Fish Physiology. Mote Marine Laboratory Technica l Report No. 1176 (MARFIN Grant # NA17FF2010). 75 p. Collins, M. R., J.C. McGovern, G.R. Sedberry, H. Scott Meister, and R. Pardieck. 1999. Swim bladder deflation in black sea ba ss and vermilion snapper: potential for increased post-release survival. North American Journal of Fisheries Management. 19: 828-832 Fnge, R. 1996. Physiology of the swim bladder. Physiological Review. 46:299-322. Feathers, M.G. and A.E. Knable. 1983. Effects of depressurization upon largemouth bass. North American Journal of Fisheries Management 3:86-90 Gitschlag, G.R. and M.L. Renaud. 1994. Fi eld experiments on survival rates of cages and released red snapper. North American Journal of Fisheries Management 14:131-136 Jarvis, E.T. and C.G. Lowe. 2008. The eff ects of barotrauma on the catch-and-release survival of southern California nears hore and shelf rockfish (Scorpaenidae, Sebastes spp.). Canadian Journal of Fisher ies and Aquatic Science 65:1286-1296 Jones, F.R.H. and N.B. Marshall. 1953. The structure and functions of the teleostean swimbladder. Biological Bulletin 28:16-83. Koenig, C. 2001. Preliminary results of depth-related capture-release mortality of dominant reef fish in the eastern Gulf of Mexico. Special report to the Gulf of Mexico Fishery Management Council.

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130 Lee, W.C. and E.P. Bergersen. 1996. Infl uence of thermal and oxygen stratification on lake trout hooking mortality. North American Journal of Fisheries Management 16:175-181. Loftus, A.J. 1991. Puncturing air bladders: successful release method? SFI Bulletin No. 426 p. 3. Lukacovic, R. and J.H. Uphoff. 2002. Hook location, fish size, and season as factors influencing catch-and-release mo rtality of striped bass caught with bait in Chesapeake Bay. p. 97-100. In: Lucy, J.A. and A. L. Studholme (eds.) Catch and Release in Marine Recreational Fisheries. American Fisheries So ciety, Symposium 30, Maryland. Marshall, N.B. 1970. ‘Poissons sans poids’. The Life of Fishes. Universe Books. New York. p 67-80. Murphy, M.D., R.F. Heagey, V.H. Neugeba uer, M.D. Gordon a nd J.L. Hintz. 1995. Mortality of spotted seatrout released from gill-net or hook-and-line gear in Florida. North American Journal of Fisheries Management 15:748-753. Pelster, B. 1997. Buoyancy. p. 25-42. In: Evans, D. (ed.) The Physiology of Fishes 2nd edition. CRC Press. Queensland, FMA, Australia. 1989. Maximizing survival rates of released fish, how to release fish with in flated air bladders. Render, J.H. and C.A. Wilson. 1994. Hook-andline mortality of caught and release red snapper around oil and gas plat form structural habitat. Bulletin of Marine Science 55:1106-1111. Render, J.H. and C.A. Wilson. 1996. The effect of gas bladder deflat ion on mortality of hook-and-line caught and released red snappe rs: implications for management. p.244253. In: Arreguin-Sanchez, F., J.L. Munro, M.C. Balgos and D. Pauly (eds.) Biology and culture of tropical groupers and snappers. International Ce nter for Living, Aquatic Resources Management Confer ence Proceedings 48, Makati City, Philippines. Rogers, B.L., C.G. Lowe, E. Fernndez-Juri cic and L.R. Frank. 2008. Utilizing magnetic resonance imaging (MRI) to assess the e ffects of angling-induced barotraumas on rockfish (Sebastes). Canadian Journal of Aquatic Science 65:1245-1249. Rummer, J.L. and W.A. Bennett. 2005. Physiological effects of swim bladder overexpansion and catastrophic decompression on red snapper. Transactions of the American Fisheries Society 134:1457-1470

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131 Rummer, J.L. 2007. Factors affecting catch-a nd-release (CAR) mortal ity in fish: insight into CAR mortality in red snapper and the influence of catastrophic decompression. p. 123-144. In: Patterson, W.F., III, J.H. Cowan, Jr., G.R. Fitzhugh, and D.L. Nieland, (eds.). Red Snapper Ecology and Fisheries in the U.S. Gulf of Mexico. American Fisheries Society, Symposium 60, Bethesda, Maryland. Shasteen, S.P. and R.J. Sheehan. 1997. La boratory evaluation of ar tificial swim bladder deflation in largemouth bass: potential be nefits for catch-and-release fisheries. North American Journal of Fisheries Management 17:32-37. Schisler, G.J. and E.P. Bergersen. 1996. Postrelease hooking mortal ity of rainbow trout caught on scented artificial baits. North American Journal of Fisheries Management 16:570-578. Schirripa, M.J., K.M. Burns and J.A. Bohnsack 1993. Reef fish release survival based on tag and recovery data. Southeast Fish eries Center Contribution No. MIA 92/93, Miami, Florida. Schirripa M.J. and K.M. Burns. 1997. Growth estimates for three species of reef fish species in the eastern Gulf of Mexico. Bulletin of Marine Science 61:581-591. Taylor, M.J. and K.R. White. 1992. A meta-analysis of hooking mortality of nonanadromous trout. North American Journal of Fisheries Management 12:760-767. Theberge, S. and S. Parker. 2005. Releas e methods for rockfish. Oregon Sea Grant, Corvallis, Oregon, No. ORESU-G-05-001. Wilde, G.R., M.I. Muoneke, P.W. Bettoli, K.L. Nelson and B.T. Hysmith. 2000. Bait and temperature effects on striped bass mortality in freshwater. North American Journal of Fisheries Management 20:810-815. Wilde, G.R. 2009. Does venting prom ote survival of released fish? Fisheries 34(1):20-28. Wilson, R. 1993. An in –situ study of the survivorship of the undersized bycatch in the red grouper fishery. MARFIN grant # NA17FF0387-01. 39 p. Wilson, R.R. and K.M. Burns. 1996. Potent ial survival of rel eased groupers caught deeper than 40 m based on shipboard and in situ observations, and tag-recapture data. Bulletin of Marine Science 5(1):234-247.

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132 Chapter Four: Red Grouper ( Epinephelus morio ) Movement Patterns in the Eastern Gulf of Mexico and South Atlantic off the State of Florida Abstract Although data analyzed for this chapter cam e from studies originally designed to determine undersized bycatch su rvival in the reef fish r ecreational-for-hire, private recreational and commercial l ong-line fisheries in the eastern Gulf of Mexico and South Atlantic off the Florida east coast, some general movement trends for red grouper were discernable. Data were anal yzed by plotting original capture and recaptures within a GIS and by calculating the distance between points. Coordinates of locati ons (to the nearest minute, to protect exact fish ing sites) where fish were caught were exported to a Geographical Information System (GIS) deve loped using ArcGIS 9.x (ESRI, 2004) to perform spatial analyses. Since fishers repor ted tagging and recapture locations to the nearest minute of latitude and longitude, and based on Florida’s proximity to the equator, the definition of movement used in this study wa s travel of at least 1 minute or 3 km from the original tagging site. This spatial reso lution of reporting imposed restrictions on analysis, therefore only moves gr eater than 3 km were credited as actual movement. Fish movement patterns were analyzed with re gard to size, bathymetry and hurricane occurrence. A chi square test was used to dete rmine if fish size was related to movement. Separate tests were run for th e Gulf of Mexico and Atlantic Most red grouper were site faithful and fish tended to be larger with dist ance from shore. However for fishes that did exhibit long distance movement s a stepwise, forward logi stic regression red grouper

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133 movement model was developed to determine if long distance movements were the result of hurricanes and tropical storms. Fish m ovements in the eastern Gulf of Mexico (n=1,011), Florida Keys (n=29) and the South Atlantic off the Flor ida east coast (n=49) were analyzed. The model indicated two t ypes of movement: 1) individual fish movements by depth (changes of depth of 5m 10 m, and 20m) and 2) movement by multiple (48) groups of similar sized small to medium (25.4-49.5 cm) sized red grouper (cohort movement). Most movement involved red grouper 38.1 cm; the length at which tissue in the posterior portion of the vent ral wall of the red grouper swim bladder became vascularized and additional gas gla nd cells developed to provide additional buoyancy While hurricanes have been documented to influence red grouper movements (Franks 2003), model results showed that a lthough some fish move d during periods when tropical storms or hurricanes were present, other red grouper moved in their absence. Movement due to named tropical storms or hurricanes was not significant. The two significant variables identified by the model we re number of days at large between tag and recapture and length at recapture (p<0.001). A second model was developed to examine red grouper movement in relation to depth based on groups of fish that changed depth by a minimum of 5 m, 10 m, 20 m and fish that did no t change depth or exhibited zero movement. At the 5m depth difference level, re capture length a nd growth were significantly different; but ta gging length was not. At 10m and 20 m differences of both tagging and recapture lengths and growth were significantly different. In all cases, fish that moved into deeper water exhibited gr eater growth than those that did not move.

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134 Introduction Discerning fish movement and migration patterns is of critical importance in understanding the life history of fishes (Cushing 1981). Fishery management depends upon knowledge of the all habitats required by different fish life stages as fish progress from egg to adult. This information ha s become increasing important as agencies transform management strate gies from single species management to ecosystem management (Witherell 2004, U.S. Commi ssion on Ocean Policy 2004). Just as the minimum size limit has been the cornerstone of traditional fisheries management, marine protected areas (MPAs) have become the foundation of ecosystem management (Bohnsack 1993, Bohnsack and Ault 1996, Pew 2003, Ault et al. 2006). Inherent in this concept of fisheries management is the tenant that MPAs provide prime habitat for fish breeding stock that will provide future re cruits to depleted areas through spillover (Bohnsack 1994). Knowledge of fish movements as relate d to habitats, seasons and function for each life stage is necessary for cr eating better reserves (Crosby et al. 2000, Meester et al. 2001, Meester et al. 2004, Hu mston et al. 2004, Nowlis and Friedlander 2004). Many fishes move to utilize different ha bitats, from feeding grounds to spawning grounds, where the larvae are transported by currents to nursery grounds, and from nursery grounds to grow until they are large enough to join adults on the feeding grounds completing the cycle. Red grouper follow this strategy, spawning o ffshore and utilizing currents to transport larvae to inshore nursery grounds. Thus current speed, direction and transport play important roles in transporting fish from one habitat to another (Helfman

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135 2007). Red grouper utilize shallow inshore ha bitats as nursery grounds and move to deeper offshore habitats as they mature. Li ke many reef fish species, red grouper exhibit site fidelity over long periods of time although extensive mo vements by some “vagrants” have been documented (Moe 1966, Bullock and Smith 1991, Koenig and Coleman 2006). Current knowledge of fish life history appears to profit fish that do not exhibit movement over vagrants (Bohnsack 1996) but there must be a biological advantage to vagrants, whether it is colonization of new territory or maintaining genetic homogeneity; thus it important to investigate their movement s and contributions to the species. The tag/release study provided useful red gr ouper movement data. Although most fish did not move, analyses were conducted on those that did in an attempt to determine the purpose of the movements detected. Hurricanes have been documented to influence red grouper movement (Franks 2003). A forward logistic regression red grouper movement model was developed to determine if long dist ance movements detected in the database were influenced by hurrican es and tropical storms. Methods Fish Tag and Release Fish Tagging Undersized red grouper were tagged by Mote Marine Laboratory ( MML) staff, student interns and volunteers, as well as by charter boat and headboat captain s and crew, private recreational and commercial fi shers throughout the eastern Gulf of Mexico and off the

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136 southeastern Florida coast (Figure 4-1) as co mponents of a variety of funded studies to determine undersized reef fish bycatch survival. All red grouper were tagged using single-barbed Hallprint plastic dart tags inserted at an angle next to the anterior portion of the dorsal fin. These tags have already been used successfully in MML's Reef Fish Tagging Program. Data collected included ta gging date, gear type tag number, time of day, bait used, water depth, fork length in inches, fish condition upon release, amount of time the fish was out of the water, whether or not the fish was vented and the capture location to the nearest one degree of latitude and longitude. Tag information included tag number and the 1-800 toll-free dedicated te lephone number at Mote. The telephone was answered personally during work hours and calls regarding tag return information were recorded on weekends, holidays and ev enings by an answering machine. Figure 4-1. Study area including long distance movements of tagged and recaptured red grouper.

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137 Return data including tag number, date of cap ture, gear type, bait t ype, water depth, fork length in inches, capture locat ion, overall condition of the fish and of the area around the tag insertion site and whether the fish was ke pt or released, were recorded. Data were entered on a PC computer using Paradox software into a temporary file. A second individual proofed the entered data against the original data sheet. If no errors were detected or after errors were corrected, data were then transferred electronically into the permanent reef fish database. Since fishers reported tagging and recaptu re locations to the nearest minute of latitude and longitude, and based on Florida’s proximity to the equator, the definition of movement used in this study wa s travel of at least 1 minute or 3 km from the original tagging site. Publicity Campaign and Tag Lottery To increase recapture repor ting, a publicity campaign in cluding MML press releases presentations at scientific conferences and fishing club meetings and publication of information in various issues of a MARFIN funded Reef Fish Survival Study (RFSS) newsletter, were used to disseminate proj ect objectives and results. Copies of the newsletter were sent to all study participants as well as to fisheries scientists, fishery management agencies, industry representa tives, and newspaper “Outdoor” writers and fishing magazine writers, who re quested them. In addition, a tag lottery was held at the end of each year. The winning tag was chosen from all tags returned during that year. Both the tagger and the person re turning the tag each received $100.

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138 Data Analyses Length/frequency data for red grouper were u tilized to examine fish length (cm) with distance (km) from shore at time of tagging in the South Atlantic o ff Florida and in the eastern Gulf of Mexico. A length/frequency hi stogram of fish lengths (cm) at original capture was constructed by placing fish lengths in 5 cm wide bins. Regressions of mean fish lengths (representing count s of 10 or more fishes) versus original capture distance from shore (km) were superimposed upon the length/frequency histogram. Regressions of the r of the means and the r of each indi vidual fish were drawn. No means were calculated for categories with less than 10 fishes A line of best fit for the regressions was calculated using the equation y = m*x + b, where y = distance from shore (km), m = slope, x = fish length (FL in cm) and b = y intercept. A linear regression was then run on the regression using all fish lengths to dete rmine if results were significant, i.e. the relationship between the two variables (fis h length and distance from shore) were significantly correlated. Data were analyzed for general distributional tre nds and size-depth relationships. Red grouper movement was mapped by plotting capture and recaptur es within a Geographical Information System (GIS) and by calcula ting distance between points. The spatial resolution of reporting (one minute of latitude and longitude) imposed restrictions on this analysis, therefore only moves gr eater than 3 km were used in analyses. Coordinates of locations (to the nearest minute, to protect exact fishing sites) wh ere fish were caught were exported to a GIS deve loped using ArcGIS 9.x (ESRI, 2004) to perform spatial

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139 analyses. Fish movement patterns were anal yzed with regard to movement with size, bathymetry and hurricane occurrence. Ancillary data, such as bathymetry were acquired from the state of Florida’s Geographic Data Library (2004). These data were used to produce geo-referenced maps of locations where red grouper and red snapper were ta gged and recaptured by projecting movement data in local UTM NAD 83 coor dinate systems (16N and 17N in the Gulf and 18N in the Atlantic). Sigmaplot, Oriana, and GEODIST N (Syrjala 1996) were used to perform statistical analyses. A chi square test was us ed to determine if fish size was related to movement. Tests were run for both the eastern Gulf of Mexico and South Atlantic. Red Grouper Movement Model Possible fish movement induced by hurricane s and tropical storms was examined by a stepwise, forward logistic regr ession model. The model test ed for relations hips between movement and environmental or demographic fa ctors. The dependent variable, a binary categorical variable, was whether a fish moved or not (movement defined as one minute of latitude or longitude). Independe nt variables included whether or not a hurricane or named tropical st orm occurred in the study area during each individual fish’s time at large, length at tagging, length at recapture, depth at taggi ng (extrapolated from the National Geophysical Data Center’s Co astal Relief Model, Divins and Metzger 2007), depth at recapture (also from the Coas tal Relief Model), days at large, growth during time at large, and ge ographic region (eastern Gulf of Mexico, Florida Keys, or South Atlantic off the Florida east coast.

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140 Red Grouper Movement in Relation to Depth Differences in fishes that moved within dept h and those that moved between depths were examined by first sampling the depth at ta g and recapture from the National Geophysical Data Center’s Coastal Relief Model (Divins a nd Metzger 2007). At locations where fish were very close to land, model accuracy can resu lt in fish appearing to be in very shallow water or on land (depths of > 1m or positive elevations). These fish were removed from the analysis leaving 1,090 fishes included in analyses. The difference between tag and recapture depth for each fish was calculated. Fishes were classified into four groups: those that changed depth by at least 5 m, at least 10 m, and at least 20 m. Length at tagging, length at recapture, and growth were compared for fishes by depth group using a Mann-Whitney U test. Red Grouper “Cohort Movement” Data were examined for occurrences of mu ltiple similar sized fishes moving from one location to another. The criteria for group m ovement were that all fishes needed to be tagged at the same location, on the same date, and recaptured together at a second identical location, on the same date. Gr oups were mapped and data summarized in a table. Results Red Grouper At total of 16,753 red grouper tag and release events (includes some recaptured fish rereleased) occurred between October 1990 and Ju ly 2007. Total number of fish tagged and released was 15,724. Recapture coordinates were reported for 96.2% of recaptured fish.

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141 Of these 1,204 (7.7%) fish were recaptured at least once; an additional 151 fish were recaptured multiple times (Table 4-1). Most red grouper (98%) were tagged and Table 4-1 Number of single and multiple red grouper recaptures from October 1, 1990-July 31, 2007. Number of Recaptures Number of Times Recaptured 1,0531 1242 183 54 25 16 17 recaptured in the Gulf of Mexico as opposed to 2% from the South Atlantic. Fish were tagged and released by privat e recreational (13.9%), recr eational-for-hire (69.0%) and commercial (12.4%) fishers. The remainder included 0.2% tagged and released during research cruises and 4.5% with insufficient data to determine fishing sector. Gear types included rod and reel, electr ic rod and reel and comme rcial bottom long-line. Most recaptures were reported caught off headboats (42.3%), followed by those caught by recreational fishers (22.2%) a nd charter vessels (13.6%) sect or. Fish caught ranged in size from 14.6-114.3 cm at orig inal capture and from 20.381. 3 cm at recapture. Days of freedom ranged 0-4, 677 days. Fish tagge d inshore off headboats but recaptured by commercial long-line gear ranged from 37.5-58.4 cm when tagged and 45.7-90.8 cm when recaptured. Days of freedom for thes e fish ranged 43-1,309 days. These recaptures illustrate the offshore movement of red grouper and their transfer from inclusion in the inshore recreational-for-hire fishery to the o ffshore commercial long-line fishery. Red grouper tagged off commercial long-line (n =1,238) and bandit (el ectric reel) (n=328) vessels and recaptured (long-line: n=52; bandi t: n=16) included fish which ranged in size

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142 from 30.5-62.2 cm at release and 33.0-68.6 cm at recapture. Fish were at liberty for anywhere from 3-2,172 days after release. Of 1,204 red grouper recaptures, 42.9% e xhibited zero movement and 15.4% were recaptured within 3 km of the release site. None of these fish (58.3%) was used in the analyses because movement was defined as a fish having been recaptured > 3 km from the original tagging site. However, some fish (6.1%) did exhibit long distance movements of 50 km or greater (Figure 4-1). The greatest distance traveled was for a fish that had traveled 360.3 km from the re lease site. Four red gr ouper were reported to have traveled from the Gulf to the South Atlantic but these r ecaptures could not be verified. Red Grouper Movement Model A complete summary of the variables used in the stepwise, forward l ogistic regression model applied to test for significant relati onships between movement and environmental or demographic factors is found in Table 4-2. The model was based on the following parameters: 1) time frame for red groupe r tagged and recaptured (October 1, 1999July 31, 2007), 2) total number of fish tagged (n=16,753 [includes some recaptures]), 3) total number of unique fish (tagged and released only once) (n=15,724), and 4) total recaptures (n=1,204) of fish recaptured at least once.

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143 Table 4-2. Summary of variables and results of logistic regression movement model. Significant variables (p<0.05) were Length at recapture (TL cm) and Days at Large. Variable Mean St Dev Min Max Exp (B) 95% CI for exp (B) p -value Move 0.376 0.485 0 1 Hurricane (Y=1,N=0) 0.275 0.447 0 1 0.669 Length at tag (TL cm) 39.311 6.789 20.32 76.2 0.592 Depth at tag (Meters) -21.992 15.836 -231 0 0.191 Length at recap (TL cm) 42.525 8.43 20.32 81.28 1.112 1.0631.163 0.000 Depth at recap (Meters) -22.911 21.628 -511 0 0.059 Days at large 141.102 197.104 2 1801 1.002 1.0011.003 0.000 Growth (cm) 3.2131 4.747 0 27.94 0.592 Atlantic (Y=1,N=0) 0.044 0.204 0 1 0.324 Keys (Y=1,N=0) 0.025 0.157 0 1 0.737 Gulf (Y=1,N=0) 0.931 0.253 0 1 0.450 Not all recaptures were used in the model. Those that occurred on the same day they were tagged or recaptured multiple times in one day were deleted from the file. After data “clean up,” 1,090 recaptures were exam ined for relationships between movement and environmental and/ or demographic factor s. From these, moves from 408 recaptures were used because they fit the criteria. The stepwise logistic regression identified two variables as significant: number of days at large between tag and recaptu re, and length at recapture (p<0.001, Table 4-2). The model indicates a moderately good fit (-2LL, Cox and Snell R2=0.088 and Nagelkerke R2=0.120). Exp(B) for days at large was 1. 003, indicating for every additional day an

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144 animal is at large, the odds of moving increa se by 0.3%, when length at recapture is held constant. Exp(B) for length at recapture was 1.112, indica ting that for every 2.5 cm increase in length of a fish at recapture the odds of moving increase by 1.12%, when days at large are held constant. The model indicated two types of movement The first type wa s individual fish movements across depth contours with changes in depth of at least 5 m, 10 m, and 20 m associated with growth (movement with ontogeny). The second type was movement by multiple groups of similar sized small to medium (25.4-49.5 cm) sized red grouper, both immature (44%) and mature (56%) often but not exclusively within depth contours. Red Grouper Movement in Relation to Depth In both the South Atlantic o ff Florida and eastern Gulf of Mexico the trend was for smaller red grouper to be found inshore and pr ogressively larger fish to occur with increasing mean distance from shore (Figure 42). Linear regression calculations showed an r2 value of 0.926 for mean fish lengths and an r2 of 0.043 for all fish lengths in the Atlantic and an r2 value of 0.741 for mean fish lengths and an r2 of 0.163 for all fish lengths in the Gulf of Mexico. Regression coefficients are shown as Table 4-3. The linear regressions run on the regression using all fish lengths (off bot h Florida coasts) to determine if results were significant, i.e., th e relationship between th e two variables (fish lengths and distance from shor e) were significantly correlated was significant for both the Atlantic and eastern Gulf of Mexico (p < 0.001).

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145 Atlantic Gulf of MexicoNumber of Red Grouper 0 10 20 30 40 50 60 Length (cm) 05101520253035404550556065707580 Distance to Shore at Tagging (km) 5 10 15 20 25 30 35 40 45 50 r2 = 0.926 r2 = 0.043 r2 = 0.741 r2 = 0.163Number of Red Grouper 0 500 1000 1500 2000 Length (cm) 05101520253035404550556065707580 Distance to Shore at Tagging (km) 0 10 20 30 40 50 60 70 80 90 100 n=336 n=16,368 Figure 4-2. Graph of a first order linear regression (red line) through the means (red circles) of red grouper lengths (cm) 10 per size class and a first order regression through all fish lengths (cyan dotted line) of fish size by distance from shore superimposed over a length/frequency graph of red grouper captured in the South Atlantic off the Florida east coast and eastern Gulf of Mexico.

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146 Table 4-3. Results of linear regression on re gression using all fish to test the relationship between fish length and distance from shore for significance for red grouper caught and measured in the South Atlantic off the Florida east coast. RED GROUPER ATLANTIC Linear Regression Column 1 = distance to shore. Column 2 = fish length Col 1 = 19.585 + (0.323 Col 2) N = 332 R = 0.208 Rsqr = 0.0434 Adj Rsqr = 0.0405 Standard Error of Estimate = 11.194 Coefficient Std. Error t P Constant 19.585 3.469 5.645 < 0.001 Col 2 0.323 0.0835 3.868 < 0.001 Analysis of Variance : DF SS MS F P Regression 1 1874.935 1874.935 14.963 < 0.001 Residual 330 41351.601 125.308 Total 331 43226.536 130.594 RED GROUPER GULF Linear Regression Column 1 = distance to shore. Column 2 = fish length Col 1 = -18.275 + (1.457 Col 2) N = 15985 R = 0.407 Rsqr = 0.165 Adj Rsqr = 0.165 Standard Error of Estimate = 25.890 Coefficient Std. Error t P Constant -18.275 0.966 -18.925 < 0.001 Col 2 1.457 0.0259 56.270 < 0.001 Analysis of Variance : DF SS MS F P Regression 1 2122324.057 2122324.057 3166.297 < 0.001 Residual 15983 10713177.005 670.286 Total 15984 12835501.063 803.022 Movement offshore with ontogeny was clearl y visible as small undersized red grouper tagged off recreational-for-hire and privat e recreational vessels near shore were recaptured offshore in deeper waters by comme rcial reef fish long-line and bandit fishers (Figure 4-3). Fish that move d across contour depths could also be distinguished from those that did not by differences in size and growth rates (Table 4-4).

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147 Figure 4-3. Red grouper movements plotted from recaptures. Because latitude and longitude were recorded to the nearest minute, not second, to pr otect exact fishing spots, red grouper tagged and released just offshore, appear as if on land. Most recaptures show ontogenic movement offshore.

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148 At the 5 m depth difference level, recaptu re length and growth were significantly different; but tagging length was not. Fish that changed depth by 5 m had a greater recapture length and exhibited more growth than those that did not change depth. At the 10 m depth difference level, all factors (ta gging length, recapture length, and growth) tag length cm recap length cm Growth cm mean 39.294 42.113 2.819 st dev 6.756 8.128 4.318 no change n 890 890 890 mean 39.980 45.187 5.207 st dev 6.985 9.271 5.994 5 meters of depth change n 199 199 199 mean 39.319 42.266 2.946 st dev 6.756 8.204 4.420 no change n 1025 1025 1025 mean 41.123 49.291 8.168 st dev 7.308 9.211 6.897 10 meters of depth change n 64 64 64 mean 39.345 42.443 3.124 st dev 6.779 8.295 4.637 no change n 1057 1057 1057 mean 42.228 50.129 7.902 st dev 7.051 9.156 6.109 20 meters of depth change n 32 32 32 Table 4-4: Summary statis tics for fish movement in relation to changes in depth during movement. Fish were classified into two groups; 1) (labeled as change) those whose movements resulted in a change in depth of 5 m, 10m, and 20m and 2) (labeled as no change) those that either did not move or whose movement did not result in a chan g e of the s p ecified ma g nitude. The fish that did not

PAGE 165

149 were significantly different. Fish that ch anged depth by 10 m had greater tagging and recapture lengths and grew more than those th at did not. Like those that changed depth by 10 m, at the 20 m difference, all factors (t agging length, recaptur e length, and growth) were different. Fish that changed dept h by 20 m had greater tagging and recapture lengths and growth than those that did not. It should be noted that in all cases, the proportion of fish that changed depths compar ed to those that did not move or did not change depth was very small; which may skew statistical results in some cases. Red Grouper “Cohort Movement” Individuals (n=126) within fo rtyeight red grouper groups ranging in size from 25.449.5 cm appeared to have moved together (T able 4-5). Movement distances ranged from 3.2 km to 120.3 km (mean = 13.55, sd =23.62) and group size ranged from 2 fish to 6 fish (mean = 2.63, sd =1.00). Group movement occu rred in both the Gulf of Mexico near the Florida Panhandle (Figure 4-4) and in th e eastern Gulf of Mexico (Figure 4-5). Movement was documented to occur during all m onths of the year with the exception of April and within 13 of the 16 years of the st udy. Fish length (at tagging and recapture) in movement groups did not differ from t hose not in movement groups (U=62675.5, p=0.651 and U=61871.0, p=0.495, respectively), nor did growth that occurred between captures (U=64160.5, p=0.977); however, for the most pa rt fish lengths within each group were similar.

PAGE 166

150 Table 4-5. Groups of red grouper that appeared to move togeth er. Fish were tagged on the same date at the same location and we re recaptured on a different data at a different location. In some cases, groups moved similarly but at different dates; see notes. Depth is e xpressed as elevation so depth readings are expressed negative. TAG # TAG DATE RECAP DATE GROUP # DIST MOVED (km) TAG LENGTH (cm) TAG DEPTH (m) RECAP LENGTH (cm) RECAP DEPTH (m) DAYS OUT GROWTH (cm) NOTES 1008 1/24/1991 4/30/1992 1 120.31 25.40 -11.23 30.48 -35.43 462 4.54 1009 1/24/1991 4/30/1992 1 120.31 30.48 -11.23 35.56 -35.43 462 4.54 1270 1/26/1991 2/13/1991 29.7035.56-8.8735.81-13.98182.64 1277 1/26/1991 2/13/1991 29.7041.91-8.8743.18-13.98183.04 1281 1/26/1991 2/13/1991 29.7030.48-8.8730.48-13.98182.54 1284 1/26/1991 2/13/1991 29.7035.56-8.8735.56-13.98182.54 8512 9/7/1991 6/18/1992 3 63.81 33.02 -26.49 35.56 -22.97 285 3.54 8523 9/7/1991 6/18/1992 3 63.81 36.83 -26.49 40.64 -22.97 285 4.04 8533 9/7/1991 6/18/1992 3 63.81 39.04 -26.49 40.64 -22.97 285 3.17 4287 12/7/1991 8/3/1992 44.8948.26-24.5755. 88-21.992405.54SAME MOVEMENT AS GROUP 5 4289 12/7/1991 8/3/1992 44.89 33.02-24.5755.8821.9924011.54 4299 12/7/1991 8/3/1992 44.89 35.56-24.5746.9921.992407.04 4251 12/24/1991 8/3/1992 5 4.89 40.64 -24.57 43.18 -21.99 223 3.54SAME MOVEMENT AS GROUP 4 4252 12/24/1991 8/3/1992 5 4.89 41.91 -24.57 46.99 -21.99 223 4.54 4288 12/24/1991 8/3/1992 5 4.89 35.56 -24.57 40.64 -21.99 223 4.54 8608 12/27/1991 6/7/1992 617.9933. 02-17.9040.64-10.901635.54 8609 12/27/1991 6/7/1992 617.9944. 45-17.9049.53-10.901634.54

PAGE 167

Table 4-5. (Continued) 151 10549 6/10/1992 6/17/1992 7 3.69 32.39 4.75 33.02 -2.34 7 2.79 10550 6/10/1992 6/17/1992 7 3.69 39.37 4.75 40.64 -2.34 7 3.04 10159 7/14/1992 9/4/1992 829.34 36.83-17.9036.834.35522.54 10166 7/14/1992 9/4/1992 829. 3445.72-17.9045.724.35522.54 10168 7/14/1992 9/4/1992 829.34 45.72-17.9045.724.35522.54 10174 7/14/1992 9/4/1992 829.34 44.45-17.9044.454.35522.54 10074 8/19/1992 9/4/1992 9 5.11 46.99 -22.97 46.99 -22.97 16 2.54 10080 8/19/1992 9/4/1992 9 5.11 44.45 -22.97 44.45 -22.97 16 2.54 10083 8/19/1992 10/28/1992 106.3543. 18-22.9743.18-22.97702.54 10091 8/19/1992 10/28/1992 106.3538. 10-22.9738.10-22.97702.54 10131 8/20/1992 5/21/1993 11 4.02 34.29 -26.41 38.10 -36.19 274 4.04 10138 8/20/1992 5/21/1993 11 4.02 48.26 -26.41 53.34 -36.19 274 4.54 10142 8/20/1992 7/31/1993 128.44 44.45-26.4150.8030.933455.04 10144 8/20/1992 7/31/1993 128.44 43.18-26.4148.2630.933454.54 10115 8/20/1992 9/24/1994 13 12.87 45.72 -32.81 55.88 -32.81 765 6.54 10116 8/20/1992 9/24/1994 13 12.87 43.18 -32.81 55.88 -32.81 765 7.54 10117 8/20/1992 9/24/1994 13 12.87 43.18 -32.81 55.88 -32.81 765 7.54 10119 8/20/1992 9/24/1994 13 12.87 44.45 -32.81 58.42 -32.81 765 8.04 10186 9/4/1992 2/21/1995 146.06 45.72-10.9063.504.359009.54 10191 9/4/1992 2/21/1995 146.06 49.53-10.9063.254.359007.94 2428 3/10/1993 6/20/1993 15 4.03 53.34 -24.99 55.88 -24.99 102 3.54 2430 3/10/1993 6/20/1993 15 4.03 53.34 -24.99 55.88 -24.99 102 3.54 13242 7/10/1997 7/31/1997 164.03 30.48-17.9030.4817.90212.54 13249 7/10/1997 7/31/1997 164.03 50.80-17.9050.8017.90212.54 15694 7/24/1997 8/29/1997 17 4.02 37.47 -18.51 38.10 -18.51 36 2.79SAME MOVEMENT AS GROUP 18

PAGE 168

Table 4-5. (Continued) 152 15695 7/24/1997 8/29/1997 17 4.02 34.93 -18.51 35.56 -18.51 36 2.79 17250 7/24/1997 8/29/1997 17 4.02 38.10 -18.51 38.10 -18.51 36 2.54 16413 8/5/1997 8/29/1997 184.02 31.75-18.5134.93 -18.51243.79 16415 8/5/1997 8/29/1997 184.02 38.74-18.5138.7418.51242.54 16480 8/27/1997 10/1/1997 19 3.69 34.29 -24.99 35.56 -24.99 35 3.04 16485 8/27/1997 10/1/1997 19 3.69 33.02 -24.99 33.02 -24.99 35 2.54 16503 8/27/1997 10/1/1997 19 3.69 40.64 -24.99 40.64 -24.99 35 2.54 18862 10/10/1997 4/28/1998 206.6527. 94-12.2127.94-18.512002.54 18863 10/10/1997 4/28/1998 206.6527. 94-12.2127.94-18.512002.54 15954 1/20/1998 5/27/1998 21 7.56 35.56 -12.21 35.56 -12.21 127 2.54 15964 1/20/1998 5/27/1998 21 7.56 40.64 -12.21 40.64 -12.21 127 2.54 16051 1/29/1998 3/15/1998 2212.16 33.02-25.4538.1025.45454.54 16052 1/29/1998 3/15/1998 2212.16 48.26-25.4548.2625.45452.54 16033 2/19/1998 6/2/1998 23 110.82 35.56 -26.41 38.10 -14.08 103 3.54 16038 2/19/1998 6/2/1998 23 110.82 38.10 -26.41 43.18 -14.08 103 4.54 18171 3/15/1998 5/16/1998 249.76 45.72-25.4545.7225.45622.54 18175 3/15/1998 5/16/1998 249.76 48.26-25.4548.2625.45622.54 18176 3/15/1998 5/16/1998 249.76 45.72-25.4545.7225.45622.54 18177 3/15/1998 5/16/1998 249.76 40.64-25.4540.6425.45622.54 20302 6/9/1998 6/30/1998 25 3.69 38.10 -12.21 38.10 -17.90 21 2.54 23683 6/9/1998 6/30/1998 25 3.69 26.67 -12.21 26.67 -17.90 21 2.54 23687. 6/9/1998 6/30/1998 25 3.69 26.67 -12.21 27.94 -17.90 21 3.04 23004 8/14/1998 11/21/1998 265.1730. 48-14.1235.56-21.28994.54 23007 8/14/1998 11/21/1998 265.1743. 18-14.1243.18-21.28992.54 23421 3/18/1999 6/16/1999 27 9.73 33.02 -17.90 34.93 -17.90 90 3.29

PAGE 169

Table 4-5. (Continued) 153 23428 3/18/1999 6/16/1999 27 9.73 35.56 -17.90 36.83 -17.90 90 3.04 30149 3/22/2000 7/12/2000 2821.78 45.72-17.9045.7224.991122.54 30152 3/22/2000 7/12/2000 2821.78 37.47-17.9037.47 -24.991122.54 30153 3/22/2000 7/12/2000 2821.78 44.45-17.9044.4524.991122.54 30160 3/22/2000 7/12/2000 2821.78 43.18-17.9043.1824.991122.54 34368 2/26/2001 3/15/2001 29 6.05 29.21 -12.21 29.21 -12.21 17 2.54 34369 2/26/2001 3/15/2001 29 6.05 35.56 -12.21 35.56 -12.21 17 2.54 33348 3/14/2001 7/11/2001 307.37 33.02-21.3736.2018.511193.79 33349 3/14/2001 7/11/2001 307.37 43.18-21.3745.7218.511193.54 36919 3/28/2001 5/21/2001 31 3.70 30.48 -17.90 40.64 -17.90 54 6.54 36920 3/28/2001 5/21/2001 31 3.70 39.37 -17.90 40.64 -17.90 54 3.04 36786 5/30/2001 7/25/2001 325.14 46.36-25.5446.3625.54562.54 36797 5/30/2001 7/25/2001 325.14 40.01-25.5441.9125.54563.29 36799 5/30/2001 7/25/2001 325.14 30.48-25.5431.7525.54563.04 37403 5/30/2001 7/25/2001 325.14 43.18-25.5443.7925.54562.78 40627 7/25/2001 3/20/2002 33 6.39 33.66 -18.51 41.91 -25.54 238 5.79 40632 7/25/2001 3/20/2002 33 6.39 33.66 -18.51 34.29 -25.54 238 2.79 37660 11/10/2001 11/24/2001 343.7145.72-14.1245.72-7.66142.54 37666 11/10/2001 11/24/2001 343.7130.48-14.1230.48-7.66142.54 39945 6/26/2002 7/3/2002 35 12.50 38.10 -24.99 38.10 -17.90 7 2.54 39950 6/26/2002 7/3/2002 35 12.50 35.56 -24.99 35.56 -17.90 7 2.54 45306 6/27/2003 7/10/2003 363. 2034.29-17.9034. 29-24.99132.54 SAME MOVEMENT AS GROUPS 37 AND 38 45307 6/27/2003 7/10/2003 363.20 33.02-17.9033.6624.99132.79 44999 6/27/2003 7/16/2003 37 3.20 33.02 -17.90 33.02 -24.99 19 2.54 SAME MOVEMENT AS GROUPS 36 AND 38 45304 6/27/2003 7/16/2003 37 3.20 41.91 -17.90 43.18 -24.99 19 3.04

PAGE 170

Table 4-5. (Continued) 154 45335 6/27/2003 7/16/2003 37 3.20 33.02 -17.90 33.66 -24.99 19 2.79 45339 6/27/2003 7/16/2003 37 3.20 34.29 -17.90 36.20 -24.99 19 3.29 45341 6/27/2003 7/16/2003 37 3.20 32.39 -17.90 33.02 -24.99 19 2.79 45342 6/27/2003 7/16/2003 37 3.20 38.74 -17.90 38.74 -24.99 19 2.54 45315 6/27/2003 10/4/2003 383. 2030.48-17.9031. 75-24.99993.04 SAME MOVEMENT AS GROUPS 36 AND 37 45362 6/27/2003 10/4/2003 383.20 47.63-17.9048.9024.99993.04 45626 7/2/2003 7/9/2003 39 7.39 31.12 -24.99 31.12 -24.99 7 2.54 45630 7/2/2003 7/9/2003 39 7.39 43.18 -24.99 43.18 -24.99 7 2.54 45657 7/7/2003 7/23/2003 406.06 40.01-24.9940.6424.99162.79 45658 7/7/2003 7/23/2003 406.06 31.75-24.9931.7524.99162.54 46120 7/23/2003 4/24/2004 41 9.78 33.02 -24.99 35.56 -17.90 276 3.54 46124 7/23/2003 4/24/2004 41 9.78 33.02 -24.99 38.10 -17.90 276 4.54 45260 9/8/2003 10/24/2003 4210.6740. 64-30.5843.18-21.23463.54 45262 9/8/2003 10/24/2003 4210.6745. 72-30.5848.26-21.23463.54 45263 9/8/2003 10/24/2003 4210.6743. 18-30.5850.80-21.23465.54 45272 10/24/2003 6/8/2004 43 4.62 45.72 -21.23 53.34 -30.58 228 5.54 45273 10/24/2003 6/8/2004 43 4.62 48.26 -21.23 53.34 -30.58 228 4.54 45276 10/24/2003 6/8/2004 43 4.62 35.56 -21.23 51.44 -30.58 228 8.79 45269 10/24/2003 6/28/2004 444.9748. 26-21.2350.80-30.582483.54 45275 10/24/2003 6/28/2004 444.9745. 72-21.2350.80-30.582484.54 45278 10/24/2003 6/28/2004 444.9743. 18-21.2352.07-30.582486.04 45260 10/24/2003 8/27/2004 45 5.54 43.18 -21.23 49.53 -21.23 308 5.04 45270 10/24/2003 8/27/2004 45 5.54 35.56 -21.23 40.64 -21.23 308 4.54 45277 10/24/2003 8/27/2004 45 5.54 49.53 -21.23 53.34 -21.23 308 4.04

PAGE 171

Table 4-5. (Continued) 155 45859 1/22/2004 4/17/2004 4623.59 41.91-50.1044.4557.94863.54 45864 1/22/2004 4/17/2004 4623.59 46.99-50.1046.9957.94862.54 54565 3/29/2005 4/21/2005 47 7.71 40.64 -38.50 45.72 -31.38 23 4.54 54565 3/29/2005 4/21/2005 47 7.71 45.72 -38.50 45.72 -31.38 23 2.54 57523 7/26/2007 9/4/2007 4811.08 40.64-24.9940.6424.99402.54 57525 7/26/2007 9/4/2007 4811.08 38.10-24.9940.0124.99403.29 57526 7/26/2007 9/4/2007 4811.08 48.26-24.9950.8024.99403.54 57527 7/26/2007 9/4/2007 4811.08 30.48-24.9935.5624.99404.54 57529 7/26/2007 9/4/2007 4811.08 36.83-24.9944.4524.99405.54 57531 7/26/2007 9/4/2007 4811.08 34.29-24.9935.5624.99403.04 1008 1/24/1991 4/30/1992 1 120.31 25.40 -11.23 30.48 -35.43 462 4.54 1009 1/24/1991 4/30/1992 1 120.31 30.48 -11.23 35.56 -35.43 462 4.54 1270 1/26/1991 2/13/1991 29.7035.56-8.8735.81-13.98182.64 1277 1/26/1991 2/13/1991 29.7041.91-8.8743.18-13.98183.04 1281 1/26/1991 2/13/1991 29.7030.48-8.8730.48-13.98182.54 1284 1/26/1991 2/13/1991 29.7035.56-8.8735.56-13.98182.54 8512 9/7/1991 6/18/1992 3 63.81 33.02 -26.49 35.56 -22.97 285 3.54 8523 9/7/1991 6/18/1992 3 63.81 36.83 -26.49 40.64 -22.97 285 4.04 8533 9/7/1991 6/18/1992 3 63.81 39.04 -26.49 40.64 -22.97 285 3.17 4287 12/7/1991 8/3/1992 44.8948.26-24.5755. 88-21.992405.54SAME MOVEMENT AS GROUP 5 4289 12/7/1991 8/3/1992 44.89 33.02-24.5755.8821.9924011.54 4299 12/7/1991 8/3/1992 44.89 35.56-24.5746.9921.992407.04 4251 12/24/1991 8/3/1992 5 4.89 40.64 -24.57 43.18 -21.99 223 3.54SAME MOVEMENT AS GROUP 4 4252 12/24/1991 8/3/1992 5 4.89 41.91 -24.57 46.99 -21.99 223 4.54 4288 12/24/1991 8/3/1992 5 4.89 35.56 -24.57 40.64 -21.99 223 4.54

PAGE 172

Table 4-5. (Continued) 156 8608 12/27/1991 6/7/1992 617.9933. 02-17.9040.64-10.901635.54 8609 12/27/1991 6/7/1992 617.9944. 45-17.9049.53-10.901634.54 10549 6/10/1992 6/17/1992 7 3.69 32.39 4.75 33.02 -2.34 7 2.79 10550 6/10/1992 6/17/1992 7 3.69 39.37 4.75 40.64 -2.34 7 3.04 10159 7/14/1992 9/4/1992 829.34 36.83-17.9036.834.35522.54 10166 7/14/1992 9/4/1992 829.34 45.72-17.9045.724.35522.54 10168 7/14/1992 9/4/1992 829.34 45.72-17.9045.724.35522.54 10174 7/14/1992 9/4/1992 829.34 44.45-17.9044.454.35522.54 10074 8/19/1992 9/4/1992 9 5.11 46.99 -22.97 46.99 -22.97 16 2.54 10080 8/19/1992 9/4/1992 9 5.11 44.45 -22.97 44.45 -22.97 16 2.54 10091 8/19/1992 10/28/1992 106.3538. 10-22.9738.10-22.97702.54 10131 8/20/1992 5/21/1993 11 4.02 34.29 -26.41 38.10 -36.19 274 4.04 10138 8/20/1992 5/21/1993 11 4.02 48.26 -26.41 53.34 -36.19 274 4.54 10142 8/20/1992 7/31/1993 128.44 44.45-26.4150.8030.933455.04 10144 8/20/1992 7/31/1993 128.44 43.18-26.4148.2630.933454.54 10115 8/20/1992 9/24/1994 13 12.87 45.72 -32.81 55.88 -32.81 765 6.54 10116 8/20/1992 9/24/1994 13 12.87 43.18 -32.81 55.88 -32.81 765 7.54 10117 8/20/1992 9/24/1994 13 12.87 43.18 -32.81 55.88 -32.81 765 7.54 10119 8/20/1992 9/24/1994 13 12.87 44.45 -32.81 58.42 -32.81 765 8.04 10186 9/4/1992 2/21/1995 146.06 45.72-10.9063.504.359009.54 10191 9/4/1992 2/21/1995 146.06 49.53-10.9063.254.359007.94 2428 3/10/1993 6/20/1993 15 4.03 53.34 -24.99 55.88 -24.99 102 3.54 2430 3/10/1993 6/20/1993 15 4.03 53.34 -24.99 55.88 -24.99 102 3.54 13242 7/10/1997 7/31/1997 164.03 30.48-17.9030.4817.90212.54 13249 7/10/1997 7/31/1997 164.03 50.80-17.9050.8017.90212.54

PAGE 173

Table 4-5. (Continued) 157 15694 7/24/1997 8/29/1997 17 4.02 37.47 -18.51 38.10 -18.51 36 2.79SAME MOVEMENT AS GROUP 18 15695 7/24/1997 8/29/1997 17 4.02 34.93 -18.51 35.56 -18.51 36 2.79 17250 7/24/1997 8/29/1997 17 4.02 38.10 -18.51 38.10 -18.51 36 2.54 16413 8/5/1997 8/29/1997 184.02 31.75-18.5134.93-18.51243.79SAME MOVEMENT AS GROUP 17 16415 8/5/1997 8/29/1997 184.02 38.74-18.5138.7418.51242.54 16480 8/27/1997 10/1/1997 19 3.69 34.29 -24.99 35.56 -24.99 35 3.04 16485 8/27/1997 10/1/1997 19 3.69 33.02 -24.99 33.02 -24.99 35 2.54 16503 8/27/1997 10/1/1997 19 3.69 40.64 -24.99 40.64 -24.99 35 2.54 18862 10/10/1997 4/28/1998 206.6527. 94-12.2127.94-18.512002.54 18863 10/10/1997 4/28/1998 206.6527. 94-12.2127.94-18.512002.54 15954 1/20/1998 5/27/1998 21 7.56 35.56 -12.21 35.56 -12.21 127 2.54 15964 1/20/1998 5/27/1998 21 7.56 40.64 -12.21 40.64 -12.21 127 2.54 16051 1/29/1998 3/15/1998 2212.16 33.02-25.4538.1025.45454.54 16052 1/29/1998 3/15/1998 2212.16 48.26-25.4548.2625.45452.54 16033 2/19/1998 6/2/1998 23 110.82 35.56 -26.41 38.10 -14.08 103 3.54 16038 2/19/1998 6/2/1998 23 110.82 38.10 -26.41 43.18 -14.08 103 4.54 18171 3/15/1998 5/16/1998 249.76 45.72-25.4545.7225.45622.54 18175 3/15/1998 5/16/1998 249.76 48.26-25.4548.2625.45622.54 18176 3/15/1998 5/16/1998 249.76 45.72-25.4545.7225.45622.54 18177 3/15/1998 5/16/1998 249.76 40.64-25.4540.6425.45622.54 20302 6/9/1998 6/30/1998 25 3.69 38.10 -12.21 38.10 -17.90 21 2.54 23683 6/9/1998 6/30/1998 25 3.69 26.67 -12.21 26.67 -17.90 21 2.54 23687. 6/9/1998 6/30/1998 25 3.69 26.67 -12.21 27.94 -17.90 21 3.04 23004 8/14/1998 11/21/1998 265.1730. 48-14.1235.56-21.28994.54 23007 8/14/1998 11/21/1998 265.1743. 18-14.1243.18-21.28992.54

PAGE 174

Table 4-5. (Continued) 158 23421 3/18/1999 6/16/1999 27 9.73 33.02 -17.90 34.93 -17.90 90 3.29 23428 3/18/1999 6/16/1999 27 9.73 35.56 -17.90 36.83 -17.90 90 3.04 30149 3/22/2000 7/12/2000 2821.78 45.72-17.9045.7224.991122.54 30152 3/22/2000 7/12/2000 2821.78 37.47-17.9037.4724.991122.54 30153 3/22/2000 7/12/2000 2821.78 44.45-17.9044.4524.991122.54 30160 3/22/2000 7/12/2000 2821.78 43.18-17.9043.1824.991122.54 34368 2/26/2001 3/15/2001 29 6.05 29.21 -12.21 29.21 -12.21 17 2.54 34369 2/26/2001 3/15/2001 29 6.05 35.56 -12.21 35.56 -12.21 17 2.54 33348 3/14/2001 7/11/2001 307.37 33.02-21.3736.2018.511193.79 33349 3/14/2001 7/11/2001 307.37 43.18-21.3745.7218.511193.54 36919 3/28/2001 5/21/2001 31 3.70 30.48 -17.90 40.64 -17.90 54 6.54 36920 3/28/2001 5/21/2001 31 3.70 39.37 -17.90 40.64 -17.90 54 3.04 36786 5/30/2001 7/25/2001 325.14 46.36-25.5446.3625.54562.54 36797 5/30/2001 7/25/2001 325.14 40.01-25.5441.9125.54563.29 36799 5/30/2001 7/25/2001 325.14 30.48-25.5431.7525.54563.04 37403 5/30/2001 7/25/2001 325.14 43.18-25.5443.7925.54562.78 40627 7/25/2001 3/20/2002 33 6.39 33.66 -18.51 41.91 -25.54 238 5.79 40632 7/25/2001 3/20/2002 33 6.39 33.66 -18.51 34.29 -25.54 238 2.79 37660 11/10/2001 11/24/2001 343.7145.72-14.1245.72-7.66142.54 37666 11/10/2001 11/24/2001 343.7130.48-14.1230.48-7.66142.54 39945 6/26/2002 7/3/2002 35 12.50 38.10 -24.99 38.10 -17.90 7 2.54 39950 6/26/2002 7/3/2002 35 12.50 35.56 -24.99 35.56 -17.90 7 2.54 45306 6/27/2003 7/10/2003 363. 2034.29-17.9034. 29-24.99132.54 SAME MOVEMENT AS GROUPS 37 AND 38 45307 6/27/2003 7/10/2003 363.20 33.02-17.9033.6624.99132.79 44999 6/27/2003 7/16/2003 37 3.20 33.02 -17.90 33.02 -24.99 19 2.54 SAME MOVEMENT AS GROUPS 36 AND 38

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Table 4-5. (Continued) 159 45304 6/27/2003 7/16/2003 37 3.20 41.91 -17.90 43.18 -24.99 19 3.04 45335 6/27/2003 7/16/2003 37 3.20 33.02 -17.90 33.66 -24.99 19 2.79 45339 6/27/2003 7/16/2003 37 3.20 34.29 -17.90 36.20 -24.99 19 3.29 45341 6/27/2003 7/16/2003 37 3.20 32.39 -17.90 33.02 -24.99 19 2.79 45342 6/27/2003 7/16/2003 37 3.20 38.74 -17.90 38.74 -24.99 19 2.54 45315 6/27/2003 10/4/2003 383. 2030.48-17.9031. 75-24.99993.04 SAME MOVEMENT AS GROUPS 36 AND 37 45362 6/27/2003 10/4/2003 383.20 47.63-17.9048.9024.99993.04 45626 7/2/2003 7/9/2003 39 7.39 31.12 -24.99 31.12 -24.99 7 2.54 45630 7/2/2003 7/9/2003 39 7.39 43.18 -24.99 43.18 -24.99 7 2.5445630 45657 7/7/2003 7/23/2003 406.06 40.01-24.9940.6424.99162.7945657 45658 7/7/2003 7/23/2003 406.06 31.75-24.9931.7524.99162.5445658 46120 7/23/2003 4/24/2004 41 9.78 33.02 -24.99 35.56 -17.90 276 3.54 46124 7/23/2003 4/24/2004 41 9.78 33.02 -24.99 38.10 -17.90 276 4.5446124 45260 9/8/2003 10/24/2003 4210.6740. 64-30.5843.18-21.23463.5445260 45262 9/8/2003 10/24/2003 4210.6745. 72-30.5848.26-21.23463.5445262 45263 9/8/2003 10/24/2003 4210.6743. 18-30.5850.80-21.23465.5445263 45272 10/24/2003 6/8/2004 43 4.62 45.72 -21.23 53.34 -30.58 228 5.54 45273 10/24/2003 6/8/2004 43 4.62 48.26 -21.23 53.34 -30.58 228 4.54 45276 10/24/2003 6/8/2004 43 4.62 35.56 -21.23 51.44 -30.58 228 8.79 45269 10/24/2003 6/28/2004 444.97 48.26-21.2350.80 -30.582483.54 45275 10/24/2003 6/28/2004 444.97 45.72-21.2350.80 -30.582484.54 45278 10/24/2003 6/28/2004 444.97 43.18-21.2352.07 -30.582486.04 45260 10/24/2003 8/27/2004 45 5.54 43.18 -21.23 49.53 -21.23 308 5.04 45270 10/24/2003 8/27/2004 45 5.54 35.56 -21.23 40.64 -21.23 308 4.54 45277 10/24/2003 8/27/2004 45 5.54 49.53 -21.23 53.34 -21.23 308 4.04

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Table 4-5. (Continued) 160 45859 1/22/2004 4/17/2004 4623.59 41.91-50.1044.45 -57.94863.54 45864 1/22/2004 4/17/2004 4623.59 46.99-50.1046.99 -57.94862.54 54565 3/29/2005 4/21/2005 47 7.71 40.64 -38.50 45.72 -31.38 23 4.54 54569 3/29/2005 4/21/2005 47 7.71 45.72 -38.50 45.72 -31.38 23 2.54 57523 7/26/2007 9/4/2007 4811.08 40.64-24.9940.64 -24.99402.54 57525 7/26/2007 9/4/2007 4811.08 38.10-24.9940.01 -24.99403.29 57526 7/26/2007 9/4/2007 4811.08 48.26-24.9950.80 -24.99403.54 57527 7/26/2007 9/4/2007 4811.08 30.48-24.9935.56 -24.99404.54 57529 7/26/2007 9/4/2007 4811.08 36.83-24.9944.45 -24.99405.54 57531 7/26/2007 9/4/2007 4811.08 34.29-24.9935.56 -24.99403.04

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161 Figure 4-4. Group movement by red grouper near the panhandle of Florida. Grey squares represent locations were fish were tagged, white circles represent locations were fish were recaptured.

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162 Discussion Distance from Shore and Size Distribution Fish length increased with distance from shore in both the South Atlantic off Florida and the eastern Gulf of Mexico. When the regressi on for all fish was tested for significance, Figure 4-5. Group movement by red grouper in the far eastern Gulf of Mexico. Grey squares represent locations were fish were tagged, white circles represent locations were fish were recaptured.

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163 the two variables (fish length and distance from shore) were signifi cantly correlated (for both the Atlantic and the eastern Gulf of Me xico. These data agree with life history accounts (Moe 1966, Bullock and Smith 1991, Koenig and Coleman 2006) of juvenile red grouper occupying shallow coastal locatio ns and moving offshore with ontogeny to inhabit offshore waters on the shelf. Movement The majority (62.8%) of red grouper in this st udy exhibited little or no movement within the limitations of spatial resolution. Fishes originally captured and tagged off commercial long-line vessels were recovered eith er at the original ca pture site or a few kilometers away. Although most of these fish were not legal sized, they were larger than those tagged inshore. Results are consistent with those reported by Koenig and Coleman (2006) who stated that older red grouper on th e mid-to outer west Fl orida shelf displayed high site fidelity, moving no more than 1.2 naut ical miles from their original tagging site. They ascribed this observed high site fide lity to the species’ excavation behavior (pit excavation in soft bottom sediments) and mating behavior. Unlike other grouper, red grouper do not spawn in large pelagic spawning aggregations. Instead they practice lek mating behavior where males defend defined te rritories, in this case excavated large pits (Scanlon et al. 2005, Koenig and Coleman 2006). For fish that moved two types of movement were found. The first type was individual fish movements with changes in depth asso ciated with growth. Whereas few large red grouper moved long distances, ontogenetic movements by smaller red grouper were substantial (69.2-212.4 km). Spatial analysis of fish tagged off recreational-for-hire boats

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164 and recaptured by commercial vessels demons trates the ontogenetic offshore movement from inshore waters toward deep shelf waters with increasing size described in Moe (1966) and Koenig and Coleman (2006). Data are also in agreement with life history information published by Bullock and Smith (1 991) who reported ontogenetic movement of small red grouper off Southwest Florida moving from shallow water (3-18 m) to depths greater than 36 m as fish increased size and where these fish became part of the commercial catch. In addition to the associa tion of offshore movement into deeper depth contours with fish length, most movement occurred in fish 38.1 cm; the length when tissue in the red grouper swim bladder poste rior ventral wall became vascularized and additional gas gland cells developed pr oviding additional buoyancy (Chapter 3). Red Grouper “Cohort Movement” Movement by multiple groups of similar sized small to medium (25.4-49.5 cm) sized red grouper, both immature (44%) and mature (56% ) often but not exclusively within depth contours. Tagging data from this study reveal that groups of similar sized fishes caught together on the same date at the identical location were then recaptured together on a different matching date at some other same s ite. These groups consisting of 2-6 fishes of identical or similar lengths appear to move together and movement originates from the same site on the same date. Although fish lengths (at tagging and recapture) in movement groups did not differ from t hose not in movement groups (U=62675.5, p=0.651 and U=61871.0, p=0.495, respectively), nor did growth that occurred between captures (U=64160.5, p=0.977), for the most part fish lengths within the groups was similar. These similar sized fish that travel together may have either been spawned in the

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165 same area or may “know” each other from livi ng in the same inshore area as juveniles (Jones et al. 2005). Personal observations of capture-held fish, re vealed some behaviors that may explain group movements. Red grouper captured from the same areas may “know” each other and exist in a localized social hierarchy. Hierarchies have been described for other fish species (Nakano 1994, Sloman et al. 2000, Chase et al. 2002, Whiteman and C t 2004, Grosenick et al. 2007). An established hierarchy was observed in th e behavior and associ ated coloration of captive red grouper maintained in large experimental tanks (p ersonal observation) that were captured from the same location. The alpha fish (pale beige) was the most aggressive not only to conspecifi cs but also to human caretakers. It was the first to feed and investigate new situations. The omega fish (deep maroon) was the last to feed and could be freely attacked by all other fish within the tank. No separations within the tank were required in tanks where fish were caugh t at the same location. However when fishes caught at different disparate lo cations were kept in the sa me tank no underwater barriers within the tank could prevent constant fighti ng. Two alpha (beige) fishes were observed to burrow under, jump over, push aside or bite through protective plastic mesh netting to reach each other. Fights between alpha fishes ended when one of the combatants was removed from the tank or was killed (personal observation). In addi tion to behavior, fish rank within the tank was clearly defined by colo ration. Alpha fishes were always beige in what was described as “Phase 4 of six” in Grace et al. (1994). As fishes decreased in

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166 rank, their coloration darkened to shades of li ght to darker red. Omega fish were deep maroon with white spots similar to “Phase 1 of six” described in Grace et al. (1994). While it is unknown how common or widespre ad cohort movement of red grouper might be due to the nature of fishery-dependent recaptures, forty-eight of these groups have been identified and individuals within groups appeared to have moved together. Group size ranged from 2 to 6 fishes (mean = 2.63, sd =1.00). Fishes within each group were of similar size and fish gro up lengths ranged from 25.4-49. 5 cm. These groups moved distances ranging 3.2 km to 120.3 km (mean = 13.55, sd =23.62) and occurred during all months of the year with the exception of April. Documented within 13 of the 16 continuous years of the study, group movement was noted in both the Gulf of Mexico near the Florida Panhandle and in the easte rn Gulf of Mexico. No significant long distance group movement was observed in the S outh Atlantic. This lack of observed long distance movement may be the result of substa ntially less data from the South Atlantic coupled with the narrow east coast shelf. Hurricanes In addition to ontogenetic movements of sma ll red grouper, long dist ance movements for larger red grouper have been documented. Some of these movements have been attributed to hurricanes. Franks (2003) reported the a ppearance of red grouper off Mississippi following hurricane events. After Hurricane Lili in 2002, juvenile and adult red grouper were commonly ca ught on artificial reefs a nd petroleum platforms off Mississippi where they had not previously been repor ted. Although no longer as common in these areas, red grouper are periodi cally still caught by anglers (Jim Franks,

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167 University of Southern Mississippi, Gulf Coast Marine Laboratory campus, personal communication, January 2008). However, whil e hurricanes have been documented to influence red grouper movements, results of the logistic regression indicated movement due to tropical storms or hurricanes was not significant. Alth ough some fish moved during periods when tropical storms or hurricanes were pr esent, other red grouper moved in their absence. Data from this model may not have identified hurricanes as significant because data used covered a very long time period (17 years) and an extensive geographical area. It may also be that th e criteria for movement (> 3 km) may have affected the analyses that the criteria for a hurricane was too broad as it included tropical storms. Reports of red grouper onshore/offshore moveme nts that appear unrel ated to ontogeny or hurricanes have been explai ned by commercial fishers as inshore summer feeding migrations (SEDAR 2006). Bullock and Sm ith (1991) included a comment by Bannerot mentioning seasonal offshore (27-91 m) move ments of adult red grouper in the Florida Keys. Moe (1972) reported 22 tagged red gr ouper traveled 16 mile s within 50 days. McGovern et al. (2005) found that 23% of recaptured gag (n=435) they tagged (n=3,878) off South Carolina had moved over 185 km sout hward to be recaptured off Florida at St. Augustine, Cape Canaveral, the Florida Keys and in the Gulf of Mexico. Gag that traveled the greatest distances were primarily medium sized fishes ranging 68.6-81.3 cm. They suggested that this southerly moveme nt might have been related to spawning migrations however they were unable to show seasonal movement trends. Similar to red

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168 grouper movement, the largest fish demonstr ated strong site fidelity exhibiting zero movement from original tagging sites. Genetic analyses of red grouper population stru cture found little genetic difference in red grouper from the U.S. South Atlantic, U.S. Gu lf of Mexico and the Mexican Gulf. Both larval dispersal and possible contact during the Pleistocene combined with the time scale of Ne generations for genetic mutations to occu r have been postulated to explain the genetic homogeneity (Richardson and Gold 1997, Zatcoff et al. 2004). Cohort movement may provide an additional mechan ism in preventing significant heterozygote deficiencies and prevent local and large-scale population diffe rentiation. Of the 126 fish comprising the 48 cohort groups detected in th is study, 56% were of sufficient size to reproduce Since red grouper do not aggregate to spawn and males and females cohabitate all year (Col eman et al. 1996), these small groups moving distances of 3.2 km to 120.3 km (mean = 13.55, sd =23.62) in various directions, may contribute to maintaining genetic homogeneity as a small number of i ndividuals with high re productive potential can populate an area if conditions ar e favorable (Hedgecock 1994). While it is clear that ontogenetic movements en able red grouper to utilize various habitats during different life stages, the advantage of “cohort movements” is less apparent. These fishes may be vagrants following ocean curren ts or influenced by environmental carrying capacity or forced by conspecific territorialit y to move to new areas but there must be some biological advantage or this pattern of red grouper movement would not persist

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169 over the years. Additional investigation of th is movement is necessary in understanding red grouper life history. References Cited Alverson, D.L. 1998. Discarding practices a nd unobserved fishing mortality in marine fisheries: an update. Washington Sea Gran t Program, Seattle, Washington. 76 p. Ault, J.S., S.G. Smith, J.A. Bohnsack, J. Luo, D.E. Harper and D.B. McClellan. 2006. Building sustainable fisheries in Florida’s coral reef ecosystem: positive signs in the Dry Tortugas. Bulletin of Marine Science 78(3):633-654. Beaumariage, D.S. and A.C Wittich. 1966. Returns from the 1964 Schlitz tagging program. Florida Board of Conservation Marine Research Laboratory Technical Series 47, St. Petersburg, Florida. Bohnsack, J.A. 1993. Marine reserves: they enhance fish eries, reduce conflicts, and protect resources. Oceanus 36:63-71. Bohnsack, J.A. 1994. How marine fishery reserves can improve reef fisheries. Proceedings of the Forty-third Gulf and Caribbean Fisheries Institute Conference 43(1992):217-241. Bohnsack, J.A. and J.S. Ault. 1996. Mana gement strategies to conserve marine biodiversity. Oceanography 9(1):73-82. Bohnsack, J.A. 1996. Maintenance and recovery of reef fishery pr oductivity. p. 283-313 In: Polunin, N.V.C. and C. M. Roberts (eds.) Reef Fisheries. London, Chapman and Hall. Bullock, L.H. and G.B. Smith. 1991. Seabasses (Pisces: Serranidae). In: Memoirs of the Hourglass Cruises. Vol. 8. Florida Marine Research Institute, Department of Natural Resources, St. Petersburg, FL. 243 p. Burns, K.M. 2001. Fish venting. Mo te Marine Laborator y. Available: http://isurus.mote.org/research/cfe/fishbio/how-to-vent-a-fish.htm. (September 2005). Burns, K.M. and V. Restrepo. 2002. Survival of reef fish after rapid depressurization: field and laboratory studies. p. 148-151. In: Lucy, J.A. and A.L. Studholme (eds.) Catch and Release in Marine Recreational Fisheries. American Fisheries Society, Symposium 30, Bethesda, Maryland.

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170 Burns, K.M., N.F. Parnell, and R.R. Wilson. 2004. Partitioning release mortality in the undersized red snapper bycatch: comparis on of depth vs. hooking effects. Mote Marine Laboratory Technical Report No. 932. 36 p. Burns, K.M. and B.D. Robbins. 2006. C ooperative long-line sampling of the west Florida shelf shallow water grouper comple x: Characterization of life history, undersized bycatch and targeted habitat. Mote Marine Laboratory Technical Report No. 1119. 46 p. Chase, I.D., C. Tovey, D. Spangler-Marti n, and M. Manfredoni a. 2002. Individual differences versus social dynamics in the fo rmation of animal dominance hierarchies. Proceedings of National Ac ademy of Sciences USA 99(8):5744-5749. Coleman, F.C., C.C. Koenig and L.A. Collin s. 1996. Reproductive styles of shallowwater grouper (Pisces: Serranidae) in the eastern Gulf of Mexico and the consequences of fishing spawning aggregations. Environmental Biology of Fishes 47:129-141. Crosby, M.P., K.S. Geenen, and R. B ohne. 2000. Alternative access management strategies for marine and coastal prot ected areas: a reference manual for their development and assessment. U.S. Man and the Biosphere Program, Washington, D.C. 168 p. Cushing, D.H. 1981. Fisheries biology a study in population dynamics. University of Wisconsin Press, Madison, Wisconsin. 295 p. Diamond, S.L., M.D. Campbell, D. Olson, Y. Wang, J. Zeplin, and S. Qualia. 2007. Movers and stayers: individual variability in site fidelity and movements of red snapper off Texas. p. 163-87. In: Patterson, W.F., III, J.H.Cowan, Jr., G.R. Fitzhugh, and D.L. Nieland (eds.) Red snapper ecology and fisheries in the U.S. Gulf of Mexico. American Fisheries Society, Sy mposium 60, Bethesda, Maryland. Divins, D.L. and D. Metzger 2008. NGDC Co astal Relief Model, Accessed 07 January 2008, http://www.ngdc.noaa.gov/mgg/coastal/coastal.html ESRI (Environmental Systems Research Inst itute). 2004. ArcInfo 9.0. Redlands, California. Fisher, W. 1978. FAO species identifica tion sheets for fishery purposes. (Western Central Atlantic Fishing Ar ea 310). 7 vols. Food and Ag riculture Organization FAO of the United Nations, Department of Fisheries and Oceans, Canada. Florida Fish and Wildlife Conservation Co mmission. 2005. Commercial Fisheries Landings in Florida. Available: http://research.myfwc.com/features/view_ article.asp?id=19224. (November 2005.)

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171 FGDL (Florida Geographic Data Library) 2004. Gainesville. Available: http://www.fgdl.org/ (December 2004). Franks, J.S. 2003. First record of goliath grouper, Epinephelus itajara, in Mississippi coastal waters with comments on the firs t documented occurrence of red grouper, Epinephelus morio, off Mississippi. Gulf and Caribbean Fisheries Institute 56:295306. Gold, J.R., C.P. Burridge, and T.F. Turner. 2001. A modified stepping-stone model of population structure in red drum, Sciaenops ocellatus (Sciaenidae), from the northern Gulf of Mexico. Genetica 111:305-317. Grosenick, L., T.S. Clement and R.D. Fer nold. 2007. Fish can infer social rank by observation alone. Nature 445:429-432. Grace, M., K.R. Rademacher and M. Russell. 1994. Pictorial guide to the grouper (Teleostei: Serranidae) of the wester n North Atlantic. NOAA Technical Report NMFS 118. 46 p. Hedgecock, D. 1994. Does variance in re productive success limit effective population size in marine organisms? p. 122-134. In: Beaumont, A.R. (ed.) The Genetics and Evolution of Aquatic Organisms. Chapman and Hall, London. Helfman, G.S. 2007. Fish conservation a guide to understanding and restoring global aquatic biodiversity and fi shery resources. Island Press, Washington, DC. 584 p. Hoese, H.D. and R. Moore. 1998. Fishes of the Gulf of Mexico and Adjacent Waters. 2nd edition. Texas A&M University Press, College Station, Texas. Humston, R., D.B. Olson and J.S. Ault. 2004. Behavioral assumptions in models of fish movement and their influen ce on population dynamics. Transactions of the American Fisheries Society. 133:1304-1328. Ingram, W., M. Grace, L. Lombardi-Carlson, and T. Henwood. 2006. Catch rates, distribution and size/age composition of red grouper, Epinephelus morio, collected during NOAA Fisheries Bottom Long-line Surveys from the U.S. Gulf of Mexico. SEDAR-12-DW-05. Jones, G.P., S. Planes and S.R. Thorroid. 2005. Coral reef fish larvae settle close to home. Current Biology 15(14):1314-1318. Kovach Computing Services. 2005. Oriana, version 2. Anglesey, Wales. Koenig, C. 2001. Preliminary results of de pth-related capture-release mortality of dominant reef fish in the eastern Gulf of Mexico. Report to the Gulf of Mexico Fishery Management Council. 5 p.

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172 Koenig, C.C. and F.C. Coleman. 2006. Demographics, density, and seasonal movement patterns of reef fish in the northeastern Gulf of Mexico asso ciated with marine reserves. MARFIN Grant NA 17FF2876 final report. 62 p. McGovern, J.C., G.R. Sedberry, H.S. Meister, T.M. Westendorff, D.M. Wyanski and P.J. Harris. 2005. A tag and recapture study of gag, Mycteroperca microlepis, off the southeastern U.S. Bulletin of Marine Science 76(1):47-59. Meester, G.A., J.S. Ault, S.G. Smith and A. Mehrotra. 2001. An integrated simulation modeling and operations research approach to spacial management decision making. Sarsia 86:543-558. Meester, G.A., A. Mehrotra, J.S. Ault, and E. K. Baker. 2004. Designing marine reserves for fishery management. Management Science 50(8):1031-1043. Mitsuyasu, M. and D. Fluharty. 2004. Ecosystem planning. In: Witherell, D. (ed.) Managing our nation’s fisheries: past, present and future. Proceedings of a conference on fisheries management in the Un ited States held in Washington, D.C. November 2003. 254 p. Moe, M.A., Jr. 1966. Tagging fishes in Fl orida offshore waters. Florida Board of Conservation Marine Research Laborato ry Technical Series. No. 49. p. 1-40. Moe, M.A., Jr. 1969. Biol ogy of the red grouper (Epinephelus morio Valenciennes) from the eastern Gulf of Mexico. Professional Pa per Series Marine La boratory of Florida. No. 10. 95 p. Moe, M.A., Jr. 1972. Movement and migra tion of south Florida fishes. Florida Department of Natural Resources Marine Research Laboratory Technical Series. No. 69. p. 1-25. Nakano, S. 1994. Variation in agonistic encounters in a dominance hierarchy of freely interacting red-spotted masu salmon (< i> Oncorhynchus masou ishikawai < /i> ). Ecology of Freshwater Fish. 3(4):153-158. NMFS (National Marine Fisheries Servic e). 2003. Annual Commercial Landings Statistics. Available: http://www.st.nmfs.gov/st1/commerical/la ndings/annual_landings.html (November 2005). Nowlis, J.S. and A. Friedlander. 2004. Ch apter 5. Design and de signation of marine reserves. In: Sobel, J. and C. Dahlgren (eds.). Marine Reserves. Island Press. Washington, D.C. 383 p.

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173 Pew Oceans Commission. 2003. America’s liv ing oceans charting a course for sea change. Available: http://www.pewtrusts.org/pdf /env_pew_oceans_final_report.pdf Plan Development Team. 1990. The potential of marine fishery reserves for reef fish management in the U.S. southern Atlantic. Snapper-Grouper Plan Development Team Report for the South Atlantic Fish ery Management Council. NOAA Technical Memorandum NMFS-SEFC-261, Miami, Florida. Richardson, L.R. and J.R. Gold. 1997. Mitochondrial DNA divers ity in and population structure of red grouper, Epinephelus morio, from the Gulf of Mexico. Fishery Bulletin 95:174-179. SAFMC (South Atlantic Fishery Management Council). 2005. Fishing regulations for the U. S. South Atlantic federal waters. Available: http://www.safmc.net/fishid/SAFMCregs05.pdf. (September 2005). Scanlon, K.M., F.C. Coleman and C.C. Koenig. 2005. Pockmarks on the outer shelf in the northern Gulf of Mexico: gasrelease features or ha bitat modifications by fish? Proceedings of the American Fish eries Society Symposium 41:301-312. Shpigel, M. and L. Fishelson. 1991. Experi mental removal of piscivorous grouper of the genus Cephalopholis (Serranidae) from coral habitats in the Gulf of Aq aba (Red-Sea). Environmental biology of Fishes 31:131-138. Sloman, K.A., K.M. Gilmour, A.C. Taylor, and N.B. Metcalfe. 2000. Physiological effects of dominance hierarchies within groups of brown trout, Salmo trutta, held under simulated natural conditions. Fish Physiology and Biochemistry 22(1):11-20. Smith, C.L. 1997. National Audubon Society field guide to tropical marine fishes of the Caribbean, the Gulf of Mexico, Florida, the Bahamas, and Bermuda. Alfred A. Knopf, Inc., New York, New York. Sobel, J and C. Dahlgren. 2004. Marine rese rves a guide to science, design and use. Island Press, Washington, D.C. Sturges, W. 1992. The spectrum of Loop Current variability from gappy data. Journal of Physical Oceanography 22:1245-1256. Systat Software Inc. 2004. Sigmaplot version8.02a. Richmond, California. U.S. Commission on Ocean Policy. 2004. An Ocean Blueprint for the 21st Century. Final Report. U.S. Commission on Ocean Policy, Washington, DC. 676 p. Available: http://www.oceancommission.gov/docume nts/full_color_rpt/welcome.html. Waples, R.S. 1998. Separating the wheat from the chaff: patterns of genetic differentiation in high gene flow species. The Journal of Heredity 89:438-450.

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174 Whiteman, E.A. and I.M. C t. 2004. Dominance hierar chies in group-living cleaning gobies: causes and foraging consequences. Animal Behavior 67(2):239-247. Witherell, D. editor. 2004. Managing our Nation’s Fisheries: Past, Present and Future. Proceedings of a conference on fisheries management in the United States held in Washington, D.C. November 2003. 254 p. Zatcoff, M.S., A.O. Ball and G.R. Sedberry. 2004. Population genetic analysis of red grouper, Epinephelus morio, and scamp, Mycteroperca phenax, from the southeastern U.S. Atlantic and Gulf of Mexico. Marine Biology 144:769-777.

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175 Chapter Five: Evaluation of the Efficacy of the Minimum Size Rule in the Red Grouper and Red Snapper Fisheries With Respect to J and Circle Hook Mortality and Barotrauma and the Consequences for Survival and Movement: Concluding Remarks The addition of Standard 9 to the MangusonStevens Act, prompted by national concerns regarding fisheries’ bycatch, required revision of regional Fishery Management Plans to limit bycatch. It states “Conservation and management measures shall, to the extent practicable: (A) minimize bycat ch and (B) to the extent bycatch cannot be avoided, minimize the mortality of such bycatch” (Tag art 2004). Various strategies have been employed by fishery managers to reduce by catch such as technological advances in fishing gear, catch quotas, seasonal and/or area closures and IFQs and buyouts designed to limit fishing thus reducing bycatch. A lthough these strategies may result in bycatch reduction, zero bycatch is unatt ainable and necessitates that by catch data be included in stock assessments and in comprehending ecosystem effects (Tagart 2004). Chapter One presents a brief overview of some of the issues facing undersized red grouper and red snapper fishery management off Florida. It also outlines the subject of the studies conducted to address some of these issues and to use expe rimental results as a means to evaluate the efficacy of the minimu m size rule as a tool in red grouper and red snapper management. As such, it serves as an introduction to the chapters that followed.

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176 In Chapter Two, experiments designed to ga in an understanding of how J and circle hooks affected red grouper and red snapper mortality were discussed. The first hypothesis was there was no difference in hook release mortality for red grouper and red snapper was rejected. Necropsy results from headboat client caught fish showed red snapper suffered the greatest acute hook tr auma with 49.1% mortality resulting from hooking, almost equaling all other sources ( 50.9%) of red snapper mortality combined. Only 20% of red grouper acute mortalities we re attributed to hook injuries. Similar to acute hook mortality rates, red snapper deat hs from latent hook mo rtality (29%) were much higher relative to red grouper (7%). The second and third null hypotheses tested using data from a tag/release study that th ere would be no difference in recapture rates for red grouper caught on circle and J hooks and second, that there would be no difference in recapture rates of red snapper caught on circle versus J hooks were rejected. Circle hooks reduced red grouper but not re d snapper hook mortality. Red snappers originally caught on J hooks had a slightly bette r recapture rate that those initially caught on circle hooks. The final hypothesis that hook mortality diss imilarity resulted as a consequence of differences in ecomorphology and feeding behavior was accepted. Results showed dentition, jaw lever ratios, and feeding type and feeding behavior, including prey residence time in the mouth before swa llowing differed between the two species. Although there was a difference in survival by hook type there was no relationship with fish size. Both species have a large gape at small sizes allowing small fish of both species to swallow hooks. Circle hooks are not a panacea and do not enhance survival of

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177 red snapper with regard to the minimum si ze rule; however, they do benefit red grouper and anglers should be encourag ed to use circle hooks when targeting red grouper. Depth-induced mortality caused by trauma during rapid decompression acutely impacts survival of undersized reef fish discarded in compliance with mi nimum size regulations (Render and Wilson 1994, Gitschlag and Renaud 1994, Render and Wilson 1996, Collins et al. 1999). Although many reef fish species suffer mortality from injuries caused by rapid decompression, mortality varies among sp ecies based on their anatomy, physiology, and behavior. If not allowed to return to an appropriate depth immediately, red grouper (Epinephelus morio) die from rapid decompression at sh allower depths than red snapper (Lutjanus campechanus). Although Wilson and Burns (1996) have shown that red grouper, gag, and scamp can potentially surv ive decompression in sufficient numbers to justify a minimum size rule if fish are ra pidly allowed to return to the corresponding habitat depth, differences in morphology influence survival. Red grouper had larger (in relation to body size) thinner swim bladders containing more gas than red snapper leading to larger swim bl adder ruptures than those of red snapper. Red grouper > 38.1 cm FL developed a star shaped area on the posterior swim bladder ventral wall, absent in red sn apper that incorporated some rete and a greater number of gas gland cells that would aid in gas production and increase buoyancy but would increase trauma during rapid decompression. Overall, red snapper survived rapid decompression better than red grouper because of a smaller quantity of gas in the swim bladder and less tendency to hemorrhage, especi ally in smaller fish. Swim bladders of

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178 both red groupers and red snappers rupture wi th rapid change of pr essure of 1 atm of pressure (10 m). Data from hyperbaric ch amber studies showed that while both red grouper and red snapper can eas ily survive rapid decompression from 21 m, some red grouper suffered trauma at 27 m but red sn apper did not. There were even greater differences in their ability to tolerate rapid decompression from deeper depths ( 42 m). Some red snapper did suffer mortality or s ub-lethal effects during rapid decompression from depths 40 m., however, many (60%) survived at 1 atm pressure when vented. In contrast, only 25% of red grouper survived rapid decompression from 42 m in the laboratory and never survived rapid decompre ssion from depths of 61m or greater to 1 atm pressure, even when vented (Burns et al. 2004). Results of these investigations were compared with data from red groupe r and red snapper fish tagging studies. However, at sea red grouper survival from this depth and deeper occurred when red groupers were vented and immediately allowed to return to habitat depth. This species specific difference in survival demonstr ates that morphologi cal and physiological differences between the two species dete rmine the ability to adjust to rapid depressurization. Although the effects of barotraumas aff ect both red grouper and red snapper, red grouper begin to experience di fficulties at 27.4 m whereas red snapper trauma occurs closer to 42 m. Although both species benefited from venting during laboratory studies, benefits va ried by species, depth simula tion and extent of trauma. Some red groupers caught on commercial long-l ine gear, tagged, vented and released were recaptured up to 2,172 days of free dom. Many red grouper caught in commercial fish traps at depths of 61 m were less likely to suffer severely rupt ured swim bladders. Their swim bladders were intact and inflated or if ruptured, the swim bladders had a

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179 much smaller linear or pinhole wound than red grouper caught on hooks at any depth. These fishes did not show the common extern al symptoms of rapi d depressurization. However, necropsies revealed fishes with da maged swim bladders did have gases escape into the body cavity and some of these fishes had torqued internal organs. Although red snapper survive rapid changes in depth better than red grouper, overall, swim bladder histology and cage studies and reca pture data all indicat e that smaller fish of both species survive rapid decompression fr om depth better than larger fish. These data support the minimum size rule; however, heavy predation can reverse this advantage. Additional research on predation especially by dolphins should be conducted. Analyses of data presented in Chapter Four, were used to develop movement models for red grouper and elucidate genera l movement trends for red grouper in the eastern Gulf of Mexico. Although most red grouper were site fa ithful and fish tended to be larger with distance from shore, for fishes that did exhibit long distance movements a stepwise, forward logistic regression re d grouper movement model was developed to determine if long distance movements were the result of hurricanes and tropical storms. The model indicated two types of movement: the firs t was individual fish movements across depth contours with changes of depth of at least 5 m, 10 m and 20 m associated with growth (ontogeny) and the second was movement of individuals within multiple (48) groups of similar sized small to medium (25.4-49.5 cm) sized fish (“cohort movement”), both immature (44%) and mature (56%) often but not exclusively within depth contours. While hurricanes have been documented to influence red grouper movements (Franks

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180 2003), model results showed that although some fish moved during peri ods when tropical storms or hurricanes were present, other red groupers moved in their absence. Movement due to named tropical storms or hurricanes was not found to be significant, possibly because of the large geographical area cove red by the study and analysis covering 16 years. The two significant vari ables identified by the model were number of days at large between tag and recapture and length at re capture (p<0.001). Red grouper movement in relation to depth based on groups of fish that changed depth by a minimum of 5 m, 10 m, 20 m and fish that did not change depth or exhibited zero movement showed at the 5 m depth difference level, recapture length a nd growth were significantly different, but tagging length was not. At 10m differences of both tagging and recapture lengths and growth were significantly differe nt. Fish that changed depth 20m showed the same results as those that changed depth by 10 m. In all cases, fish that moved across contour depths into deeper water exhibited gr eater growth than those that did not cross contour depths or did not move. The minimum size rule can be an efficacious t ool in red grouper and red snapper fishery management; however, factors such as regional predation can reduce its effectiveness. Combining this rule with the NMFS model of ecosystem–based management of marine fisheries would enhance survival. Mits uyasu and Fluharty (2 004) stated the NMFS Ecosystem Principles Panel defined ecosystem-based management as: “A comprehensive … management approach would require managers to consider all interactions that a target fish stock has with predators, competitors, and prey species; the effects of weather and

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181 climate on fisheries biology and ecology; the complex interactions between fishes and their habitat; and the effects of fishin g on fish stocks and their habitat.” Additionally, traditional fishery management pr actices in the Gulf of Mexico and South Atlantic have placed reef fish species into specific management groups such as the grouper/snapper complex. Problems arise when these species are tr eated as a single management unit and identical regulations are imposed on all species within the complex. Taxonomic features used to group individual sp ecies into genera and families should not be used to manage a species because indi vidual species that ev olved from a common progenitor over time adapted to fill partic ular niches. These adaptations have been encoded within the bio-mechanical functions of a species and are responsible for behavioral responses. These behavior respons es influence a species interaction with habitat, conspecifics, predators and prey. Results from this research demonstrate these responses also influence a species’ res ponse to fishing practices and gear. It should be expected that surv ival of different species with regard to fishing gear and practices will be variable dependent on the ecological role the species plays within the ecosystem it inhabits. Although much thought has been given to the effects of outside interactions, little considerat ion has been given to unders tanding the bio-mechanical functions of a species that govern physical a nd behavioral responses to fishing gear and practices that affect fish mortality and should be include d in the ecosystem paradigm.

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182 Although this study provides insights regarding red grouper and red snapper mortality from hooks and barotrauma, there are no si mple answers regarding the minimum size rule. Hook mortality can affect small red groupe r and red snapper as well as larger legal sized fish because of their large gape. Although circle hooks are beneficial for red grouper, they do not show the same favorable re sults for red snapper. This is unfortunate as red snapper suffer higher hook mortality than red grouper. Survival from rapid decompression from depth favors smaller fish of both species because of less hemorrhaging of rete and gas gland cells in th e swim bladders of smaller fish. However, this advantage can be lost if significant pred ation occurs, especially dolphin depredation. Future research should focus on investiga ting and quantifying pr edation by region as predation would favor survival of larger fish. Fish venting, a controve rsial issue, does not appear to kill red grouper or red snapper from the injection of pathogens or from injury by anglers during venting as evidenced by si milar recapture rates for vented and not vented fish in shallow water where barotrauma does not cause mortality. Venting proved useful in the laboratory in qui ckly removing escaped swim bl adder gases from the fish’s body cavity allowing the stomach muscles to pull the stomach back into place quicker than waiting for diffusion so fish were able to feed normally within a few hours. At sea, any benefits would favor benthi c species that would return to normal habitat whereas a pelagic species would need to sit on the bottom for two days until the swim bladder submucosal layer healed leaving them vulne rable to increased predation. However, venting is not a panacea and has no effect on emboli. Depth mortal ity is higher for red grouper than red snapper at comparable de pths and perhaps commercial red grouper regulation should be by tonnage. However, the reef fish recreational and recreational-for-

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183 hire fisheries tag/recapture data from off Southwest Florida show high fishing pressure for red grouper based on single and multiple re captures at shallow inshore areas. In addition to bag limits, the minimum size rule would prevent removal of small fish from inshore nursery areas where they ha ve a greater chance of survival. References Cited Burns, K., N. Parnell and R. Wilson. 2004. Partitioning release mortality in the undersized red snapper bycatch: comparis on of depth versus hooking effects. MARFIN final report No. NA97FF0349, Mote Marine Laboratory Technical Report 932. 36 p. Burns, K.M., N.J. Brown-Peterson, R.M. Overstreet, J. Gannon, P. Simmons, J. Sprinkle and C. Weaver. 2008. Evaluation of th e Efficacy of the Current Minimum Size Regulation for Selected Reef Fish Based on Release Mortality and Fish Physiology. Mote Marine Laboratory Technical Re port No. 1176 (MARFIN Grant # NA) 75 p. Collins, M.R, J.C. McGovern, G.R. Sedberry, H.S. Meister, and R. Pardieck. 1999. Swim bladder deflation in black sea ba ss and vermilion snapper: potential for increased postrelease survival. North American Journal of Fisheries Management 19:828-832. Franks, J.S. 2003. First record of goliath grouper, Epinephelus itajara, in Mississippi coastal waters with comments on the firs t documented occurrence of red grouper: Epinephelus morio, off Mississippi. Gulf and Caribbean Fisheries Institute 56:295306. Gitschlag, G.R. and M.L. Renaud. 1994. Field experiments on survival rates of cages and released red snapper. North American Journal of Fisheries Management 14:131-136. Mitsuyasu, M. and D. Fluharty. 2004. Ecosystem planning. p. 184-189. In: Witherell, D. (ed.). Managing our nation’s fisheries: past, present and future. Proceedings of a conference on fisheries management in the Un ited States held in Washington, D.C., November 2003. 254 p. Render, JH. and C.A. Wilson. 1994. Hook-andline mortality of caught and release red snapper around oil and gas plat form structural habitat. Bulletin of Marine Science 55:1106-1111.

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184 Render, J.H. and C.A. Wilson. 1996. The effect of gas bladder deflat ion on mortality of hook-and-line caught and released red sna ppers: implications for management. p. 244-253. In: Arreguin-Sanchez, F., J.L. Munro, M.C. Balgos and D. Pauly (eds.) Biology and Culture of Tropical Groupers and Snappers. International Center for Living, Aquatic Resources Management Conference Proceedings 48, Makati City, Philippines. Tagart, J. 2004. Policy perspe ctives on bycatch. p. 196-201. In: Witherell, D. (ed.) Managing Our nation’s Fisheries: Past, Present and Future. Proceedings of a conference on fisheries management in the Un ited States held in Washington, D.C., November 2003. 254 p. Witherell, D. editor. 2004. Managing our na tion’s fisheries: past present and future. Proceedings of a conference on fisheries management in the United States held in Washington, D.C., November 2003. 254 p.

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About the Author Karen Mary Burns, Bachelor of Science (University of Miami), Master of Arts (University of South Florida) is a member of the Special Mackerel Scientific and Statistical Committee of the Gulf of Mexico Fishery Ma nagement Council (1990-2009), was an Executive Committee Member (19882005) of the Association of Marine Laboratories of the Caribbean and an Invited Speaker at AFS Special Symposia (Fish Barotrauma, 2008, Ottawa, NMFS Bycatch, 2003, Quebec and Catch and Release in Marine Recreational Fisheries, 1999, Virginia ), an invited participant at NMFS 2006 Red Grouper and 2004 Red Snapper SEDAR Meetings and MEX-US GULF Coastal Pelagic Fishes Working Group (1985-1992), an invited panelist at the 2003 National Academy of Sciences NRC Committee Meeting Cooperativ e Research in the National Marine Fisheries Service, and the 1999 Florida Governor's Ocean Committee focus group on living marine resources and chaired and orga nized the 1989 AFS Larval Fish Conference.